Jing Zhang

Nature Communications, Published online: 04 August 2023; doi:10.1038/s41467-023-39883-7

Several recent works have demonstrated current based control of antiferromagnetic order, with the potential that such switching could be used for information processing and storage. Here, Haley et al demonstrate that in FexNbS2, this switching is non-local, with magnetic order changing due to an applied current at distances much larger than the spin diffusion length in the material.

Nature Materials, Published online: 14 August 2023; doi:10.1038/s41563-023-01619-9

Ferroelectricity in hafnia-based systems seems to be correlated with oxygen vacancy dynamics, but the coupling of this and ferroelectric response is rarely studied. Here it is shown that Hf0.5Zr0.5O2 can be antiferroionic, with antiferroelectric behaviour coupled to surface electrochemistry.

Nature Materials, Published online: 14 August 2023; doi:10.1038/s41563-023-01639-5

Piezoresponse microscopy and spectroscopy reveal the inextricable role of surface electrochemistry in stabilizing and controlling ferroelectricity in doped hafnia.

Nature Materials, Published online: 14 August 2023; doi:10.1038/s41563-023-01618-w

An alloy engineering approach is developed to reliably grow atomically thin bilayers with predictable and tunable moiré patterns.

Tunable excitation polarization upconversion luminescence (EPUL) is realized in Er³⁺ doped nanorods, and the degree of excitation polarization (DOEP) is regulated from 0 to 0.5, responding to the non-radiative transitions and population density of excited states. Furthermore, the polarized luminescence is applied to double anti-counterfeiting with a size as small as 10 µm.

Abstract

Excitation polarized upconversion luminescence (EPUL) from lanthanide ions has attracted considerable attention due to its wide applications in microfluidics, single particle tracking, security inks, and cell internal viscosity testing. However, controlling the degree of excitation polarization (DOEP) of the EPUL remains a significant challenge. Here, the modulation of the DOEP (from 0 to 0.5) of the EPUL from Er³⁺ doped single nanorods by changing the concentration of doped Er³⁺, Yb³⁺, or Mn²⁺ is systematically studied. By analyzing the lifetimes and disproportionate changes in luminescence intensities, it is found that optimizing Er³⁺, Yb³⁺, or Mn²⁺ concentration can reduce non-radiative transition and population density in excited states, leading to the enhancement of the DOEP under a good alignment of transition dipoles. Furthermore, the possibility of anti-counterfeiting based on such tunable EPUL is illustrated. Three kinds of fine patterns with a small size of 10 µm are realized by assembling the single nanorods accurately via optical tweezers. The patterns and their EPUL guarantee double protection for the feasibility of anti-counterfeiting. The findings of this study offer insights into the EPUL from lanthanide ions and provide a microscale platform via the EPUL for the application of multidimensional information encoding and reconfigurable double anti-counterfeiting.

Antiferromagnetic Materials

In article number 2302120, Deepak K. Singh and co-workers report the discovery of high-temperature antiferromagnetic properties in NiSi metal via neutron scattering measurements at the CORELLI spectrometer at SNS-ORNL, which can have strong implications toward spintronics research. The image shows the spin correlation of Ni ions on two non-equivalent sites, which is inferred from the modeling of elastic neutron data (shown in the background). Image credit: Oak Ridge National Laboratory/Jill Hemman.

A general synthetic strategy for fabricating single-layer hollow structures of transition metal dichalcogenides (TMDs) with high 1T-phase purity is developed by selectively etching bismuth (Bi) cores from pre-synthesized Bi@TMDs core–shell heterostructures. The obtained single-layer hollow structure of 1T-MoS₂ exhibits excellent electrochemical activity and durable stability in hydrogen evolution reactions.

Abstract

Rational design and controllable synthesis of hollow structures based on transition metal dichalcogenides (TMDs) have gained tremendous attention in the field of clean energy. However, the general synthetic strategies to fabricate single-layer hollow structures of TMDs, especially with unconventional phases (e.g., 1T or 1T′), still pose significant challenges. Herein, a scalable method is reported for the synthesis of single-layer hollow spheres (SLHS) of TMDs with high 1T-phase purity by etching bismuth (Bi) cores from pre-synthesized Bi@TMDs core–shell heterostructures including SLHS-1T-MoS₂, SLHS-1T-MoSe₂, SLHS-1T-WS₂, and SLHS-1T-WSe₂. Additionally, the etched Bi ions can be adsorbed on the single-layer TMDs shells in the form of single atoms (SAs) via the Bi─S bond. Due to the benefits of the single-layer hollow structure, high conductivity of 1T phase, and synergistic effect of Bi SAs and TMDs supports, the fabricated SLHS-1T-MoS₂ exhibits superior electrocatalytic performance for hydrogen production. This work provides a way to manufacture advanced functional materials based on the single-layer hollow structures of 1T-TMDs and to expand their applications.

Graphene

In article number 2302906 by Ondrej Dyck and co-workers, automated atomic patterning of twisted bilayer graphene is demonstrated using a scanning transmission electron microscope. Top-down electron beam irradiation is used to define attachment points in the graphene. A bottom-up, thermally controlled, atomization and diffusion process is used to supply Cu atoms, which spontaneously bond to the attachment points. This strategy holds promise for atomic precision manufacturing.

Monolayer 1H and 1T-TaTe₂ films are selectively grown by varying the substrate temperature, and a new 2 × 2 superstructure is observed upon further annealing the 1H films, leading to gap opening up to room temperature as revealed by photoemission measurements. This work demonstrates the selective control of phases and electronic structures of monolayer TaTe₂ film.

Abstract

Transition metal dichalcogenide (TMDC) films exhibit rich phases and superstructures, which can be controlled by the growth conditions as well as post-growth annealing treatment. Here, the selective growth of monolayer TaTe₂ films with different phases as well as superstructures using molecular beam epitaxy (MBE) is reported. Monolayer 1H-TaTe₂ and 1T-TaTe₂ films can be selectively controlled by varying the growth temperature, and their different electronic structures are revealed through the combination of angle-resolved photoemission spectroscopy measurements (ARPES) and first-principles calculations. Moreover, post-growth annealing of the 1H-TaTe₂ film further leads to a transition from a 19×19$\sqrt {19}{\times }\sqrt {19}$ superstructure to a new 2 × 2 superstructure, where two gaps are observed in the electronic structure and persist up to room temperature. First-principles calculations reveal the role of the phonon instability in the formation of superstructures and the effect of local atomic distortions on the modified electronic structures. This work demonstrates the manipulation of the rich phases and superstructures of monolayer TaTe₂ films by controlling the growth kinetics and post-growth annealing.

Bi_1−x Sb _x is a topological insulator with promising applications in spintronics and highly debated charge–spin conversion properties. Measurements of magnetoresistance and current-induced spin–orbit torques in Bi_0.9Sb_0.1/FeCo bilayers establish an isotropic charge–spin conversion efficiency of 1 in twin-free crystalline Bi_0.9Sb_0.1 and 0.1 in amorphous Bi_0.9Sb_0.1. Depending on temperature, thermally excited bulk carriers and the isotropic surface states contribute to the torques in crystalline Bi_0.9Sb_0.1.  

Abstract

Topological insulators have attracted great interest as generators of spin–orbit torques (SOTs) in spintronic devices. Bi_1−x Sb _x is a prominent topological insulator that has a high charge-to-spin conversion efficiency. However, the origin and magnitude of the SOTs induced by current-injection in Bi_1−x Sb _x remain controversial. Here, the investigation of the SOTs and spin Hall magnetoresistance resulting from charge-to-spin conversion in twin-free epitaxial layers of Bi_0.9Sb_0.1(0001) coupled to FeCo are investigated, and compared with those of amorphous Bi_0.9Sb_0.1. A large charge-to-spin conversion efficiency of 1 in the first case and less than 0.1 in the second is found, confirming crystalline Bi_0.9Sb_0.1 as a strong spin-injector material. The SOTs and spin Hall magnetoresistance are independent of the direction of the electric current, indicating that charge-to-spin conversion in single-crystal Bi_0.9Sb_0.1(0001) is isotropic despite the strong anisotropy of the topological surface states. Further, it is found that the damping-like SOT has a non-monotonic temperature dependence with a minimum at 20 K. By correlating the SOT with resistivity and weak antilocalization measurements, charge–spin conversion is concluded to occur via thermally excited holes from the bulk states above 20 K, and conduction through the isotropic surface states with increasing spin polarization due to decreasing electron–electron scattering below 20 K.

This review provides a systematic overview of the electrical properties of grain boundaries in polycrystalline optoelectronic materials and covers the impact of doping and passivation on carrier recombination and transport at grain boundaries. Through deliberate and rational manipulation of the grain boundaries, it is possible to achieve high-performance optoelectronic devices.

Abstract

Polycrystalline optoelectronic materials are widely used for photoelectric signal conversion and energy harvesting and play an irreplaceable role in the semiconductor field. As an important factor in determining the optoelectronic properties of polycrystalline materials, grain boundaries (GBs) are the focus of research. Particular emphases are placed on the generation and height of GB barriers, how carriers move at GBs, whether GBs act as carrier transport channels or recombination sites, and how to change the device performance by altering the electrical behaviors of GBs. This review introduces the evolution of GB theory and experimental observation history, classifies GB electrical behaviors from the perspective of carrier dynamics, and summarizes carrier transport state under external conditions such as bias and illumination and the related band bending. Then the carrier scattering at GBs and the electrical differences between GBs and twin boundaries are discussed. Last, the review describes how the electrical behaviors of GBs can be influenced and modified by treatments such as passivation or by consciously adjusting the distribution of grain boundary elements. By studying the carrier dynamics and the relevant electrical behaviors of GBs in polycrystalline materials, researchers can develop optoelectronics with higher performance.

Strong ML stimulated by handwriting force followed by persistent luminescence is observed in BaSi₂O₂N₂:Eu²⁺ at 77 K. The existence of ultra-shallow traps with a depth of 0.19–0.48 eV is responsible for this new phenomenon. Together with ML, the ultra-shallow traps also exhibit force memory ability to replicate the pre-applied force pattern simply by afterglow.

Abstract

As novel stress-sensing materials, the reported mechanoluminescence (ML) phosphors work only at or above room temperature. Herein, the ML response to low temperatures (77 K) is extended by employing ultra-shallow traps. Strong ML stimulated by handwriting force followed by persistent luminescence is observed in BaSi₂O₂N₂:Eu²⁺ (BSON) at 77 K. The UV pre-irradiated BSON can still keep the characteristics of ML with 45% intensity after 300 min. Abundant ultra-shallow traps with depth of ≈0.19 eV are found and revealed to be responsible for the low-temperature ML and persistent luminescence. Manipulation of the ultra-shallow traps is realized by doping Ge, Er, and Ce ions in BSON, leading to significant ML enhancement at 77 K. Together with ML, the ultra-shallow traps also exhibit force memory ability to replicate the pre-applied force pattern simply by afterglow. The finding advances the state-of-the-art in force sensing under low temperature conditions.

This article reviews the properties of MXene as a support material for enhancing oxygen evolution reaction (OER) performances. MXene enhances OER performance due to its ability to improve the conductivity, stability, and hydrophilicity of the catalyst. This review also highlights the advantages of MXene compared to other materials and provides future directions for utilizing MXene for various electrocatalysis.

Abstract

The harsh operating conditions of the oxygen evolution reaction (OER) in water electrolysis severely degrade the activity and stability of the electrocatalysts due to elemental leaching or particle agglomeration. Therefore, it is crucial to incorporate support materials that effectively immobilize catalyst particles for developing efficient OER catalysts. This review aims to highlight the role of MXene as a support material to improve the performance of OER catalysts. First, the extended OER mechanism is briefly described in terms of the effect of MXene support on OER catalysts. Then, various synthesis methods of MXene and catalyst-MXene compounds are introduced, and important properties of MXene that are beneficial to improve OER performances are discussed. The electrocatalytic results of the enhanced OER catalysts due to the effective MXene support are also summarized. Finally, future challenges and prospects are proposed for utilizing MXene as an excellent support material for various electrocatalysis.

Nature Nanotechnology, Published online: 14 August 2023; doi:10.1038/s41565-023-01494-0

Ultrathin ferroelectric materials, including perovskites, hafnium oxides, and van der Waals stacks are of increasing interest because they exhibit properties that are hard to achieve in bulk and because of their suitability for low-power miniaturized devices.

Interlayer twist can manipulate phonon coherence in the 2D bilayers. Through extensive simulations and analysis, the distinctive phonon properties of twisted anharmonic sheets are demonstrated, particularly the pronounced response of phonon coherence to twisting in penta-NiN₂ bilayers. These findings highlight the potential applications of 2D twisted systems in phonon-based devices.

Abstract

Twisting has recently been demonstrated as an effective strategy for tuning the interactions between particles or quasi-particles in layered materials. Motivated by the recent experimental synthesis of pentagonal NiN₂ sheet [ACS Nano 2021, 15, 13539], for the first time, the response of phonon coherence to twisting in bilayer penta-NiN₂, going beyond the particle-like phonon transport is studied. By using the unified theory of phonon transport and high order lattice anharmonicity, together with the self-consistent phonon theory, it is found that the lattice thermal conductivity is reduced by 80.6% from 33.35 to 6.47 W m⁻¹ K⁻¹ at 300 K when the layers are twisted. In particular, the contribution of phonon coherence is increased sharply by an order of magnitude, from 0.21 to 2.40 W m⁻¹ K⁻¹ , due to the reduced differences between the phonon frequencies and enhanced anharmonicity after the introduction of twist. The work provides a fundamental understanding of the phonon interaction in twisted pentagonal sheets.

Nature Materials, Published online: 03 August 2023; doi:10.1038/s41563-023-01622-0

Magnetic imaging reveals that a transport current flows in the interior of Cr-(Bi,Sb)2Te3 samples within the quantum anomalous Hall regime, contrary to the common assumption of current flow along the sample edge.

Nature Materials, Published online: 03 August 2023; doi:10.1038/s41563-023-01626-w

A van der Waals buffer layer of Sb2O3 enables the integration of high-κ dielectric layer with sub-1 nm equivalent oxide thickness on two-dimensional semiconductors, resulting in high performance of two-dimensional field-effect transistors.

Ultra-thin MXene film is crosslinked with PEDOT: PSS, resulting in a more stable, conductive, and transparent electrode that can conformably attached on skin and neural surfaces, and accurately detect very weak signals. Together with other imaging techniques, they can study brain activity in a specific cognitive task, demonstrating multimodal sensing ability of neuroelectrical signals without artifacts.

Abstract

Neuroelectrical signals transmitted onto the skin tend to decay to an extremely weak level, making them highly susceptible to interference from the environment and body movement. Meanwhile, for comprehensively understanding cognitive nerve conduction, multimodal sensing of neural signals, such as magnetic resonance imaging (MRI) and functional near-infrared spectroscopy (fNIRS), is highly required. Previous metal or polymer conductors cannot either provide a seamless on-skin feature for accurate sensing of neuroelectrical signals or be compatible with multimodal imaging techniques without opto- and magnet- artifacts. Herein, a ≈20 nm thick MXene film that is able to simultaneously detect electrophysiological signals and perform imaging by MRI and fNIRS with high fidelity is reported. The ultrathin film is made of crosslinked Ti₃C₂T_x film via poly (3,4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT: PSS), showing a record high electroconductivity and transparency combination (11 000 S cm⁻¹@89%). Among them, PEDOT: PSS not only plays a cross-linking role to stabilize MXene film but also shortens the interlayer distance for effective charge transfer and high transparency. Thus, it can achieve a low interfacial impedance with skin or neural surfaces for accurate recording of electrophysiological signals with low motion artifacts. Besides, the high transparency originating from the ultrathin feature leads to good compatibility with fNIRS and MRI without optical and magnetic artifacts, enabling multimodal cognitive neural monitoring during prolonged use.

This study reports on a robust and self-powered unidirectional analog artificial neuromorphic memristor device with a piezoelectric nanogenerator, taking inspiration from biological information processing. A self-powered unidirectional neuromorphic resistive memory device is demonstrated, comprising an ITO/ZnO/Yb₂O₃/Au structure combined with a high-sensitivity piezoelectric nanogenerator ITO/ZnO/Au.

Abstract

This study presents a method to enhance data processing by integrating a unidirectional analogue artificial neuromorphic memristor device with a piezoelectric nanogenerator, taking inspiration from biological information processing. A self-powered unidirectional neuromorphic resistive memory device is proposed, comprising an ITO/ZnO/Yb₂O₃/Au structure combined with a high-sensitivity piezoelectric nanogenerator (PENG) ITO/ZnO/Al. The memristor device is operated at a voltage sweep of ±4 V with a low operating current in a range of 1.4 µA. The filament formation is studied using a conductive mode atomic force microscope. The integration enables the creation of a self-powered artificial sensing system that converts mechanical stimuli from the PENG into electrical signals, which are subsequently processed by analogue unidirectional neuromorphic device to mimic the functionality of a neuron without requiring additional circuitry. This emulation encompasses crucial functions such as potentiation, depression, and synaptic plasticity. Furthermore, this study highlights the potential for hardware implementations of neural networks with a weight change of memristor device with nonlinearity (NL) of potentiation and depression of 1.94 and 0.89, respectively, with an accuracy of 93%. The outcomes of this research contribute to the progress of next-generation low-power, self-powered unidirectional neuromorphic perception networks with correlated learning and trainable memory capabilities.

A single layer of chalcogenide CrSiTe₃ is found to be a 2D ferromagnetic second-order topological insulator. The CrSiTe₃ monolayer exhibits a nontrivial gapped bulk state in the spin-up channel and a trivial gapped bulk state in the spin-down channel. The topological corner states of the CrSiTe₃ monolayer are spin-polarized and pinned at the corners of the sample in real space.

Abstract

2D second-order topological insulators (SOTIs) have sparked significant interest, but currently, the proposed realistic 2D materials for SOTIs are limited to nonmagnetic systems. In this study, for the first time, a single layer of chalcogenide CrSiTe₃—an experimentally realized transition metal trichalcogenide is proposed with a layer structure—as a 2D ferromagnetic (FM) SOTI. Based on first-principles calculations, this study confirms that the CrSiTe₃ monolayer exhibits a nontrivial gapped bulk state in the spin-up channel and a trivial gapped bulk state in the spin-down channel. Based on the higher-order bulk–boundary correspondence, it demonstrates that the CrSiTe₃ monolayer exhibits topologically protected corner states with a quantized fractional charge (e3$\frac{e}{3}$) in the spin-up channel. Notably, unlike previous nonmagnetic examples, the topological corner states of the CrSiTe₃ monolayer are spin-polarized and pinned at the corners of the sample in real space. Furthermore, the CrSiTe₃ monolayer retains SOTI features when the spin–orbit coupling (SOC) is considered, as evidenced by the corner charge and corner states distribution. Finally, by applying biaxial strain and hole doping, this study transforms the magnetic insulating bulk states into spin-gapless semiconducting and half-metallic bulk states, respectively. Importantly, the topological corner states persist in the spin-up channel under these conditions.

A stacking-controlled continuous precipitation strategy is proposed to synthesize uniform rBN crystalline films (lateral size of 2 × 1 cm², thickness of >1 µm) on the vicinal FeNi (111) single crystal. The rBN films with parallel stacked layers exhibit ultrahigh nonlinear optical response with the record-high frequency conversion efficiency of 1% in the 2D-material family.

Abstract

Nonlinear optical crystals lie at the core of ultrafast laser science and quantum communication technology. The emergence of 2D materials provides a revolutionary potential for nonlinear optical crystals due to their exceptionally high nonlinear coefficients. However, uncontrolled stacking orders generally induce the destructive nonlinear response due to the optical phase deviation in different 2D layers. Therefore, conversion efficiency of 2D nonlinear crystals is typically limited to less than 0.01% (far below the practical criterion of >1%). Here, crystalline films of rhombohedral boron nitride (rBN) with parallel stacked layers are controllably synthesized. This success is realized by the utilization of vicinal FeNi (111) single crystal, where both the unidirectional arrangement of BN grains into a single-crystal monolayer and the continuous precipitation of (B,N) source for thick layers are guaranteed. The preserved in-plane inversion asymmetry in rBN films keeps the in-phase second-harmonic generation field in every layer and leads to a record-high conversion efficiency of 1% in the whole family of 2D materials within the coherence thickness of only 1.6 µm. The work provides a route for designing ultrathin nonlinear optical crystals from 2D materials, and will promote the on-demand fabrication of integrated photonic and compact quantum optical devices.

Nature Materials, Published online: 31 July 2023; doi:10.1038/s41563-023-01607-z

Detailed transmission electron microscopy imaging of the dynamics of domain walls in twisted van der Waals ferroelectrics is obtained, capturing the transition to a hysteretic response.

Nature, Published online: 26 July 2023; doi:10.1038/s41586-023-06452-3

Thermodynamic evidence of fractional Chern insulator in moiré MoTe₂

The bacterial cell envelope and the biofilm matrix are major biological barriers, limiting bacterial bioavailability and propagating antimicrobial resistance. Novel anti-infectives, such as e.g. pathoblockers, designed to disarm rather than killing the bacteria, require novel functional materials for improving their delivery. Rational development of such innovative antimicrobial therapies will much benefit from complex in vitro models, preferentially human-based, as alternative to animal testing and for faster translation into the clinic.

Abstract

With the emerging problem of antimicrobial resistance, the world is facing a slow but dangerous pandemic. While the discovery of novel antibiotics is reaching a nearly exhaustive end, new concepts for anti-infective drugs are emerging. So-called pathoblockers aim to de-weaponize bacteria rather than just killing them. As the target of these molecules is typically located intracellularly, however, hitherto almost unnoticed biological barriers are emerging such as the biofilm matrix, the bacterial cell envelope, efflux pumps, and eventual bacterial metabolism. This leads to a new paradigm that is to maximize bacterial bioavailability. To overcome the bacterial barriers, especially when further optimization of the active molecules is not possible, functional materials are needed to engineer innovative delivery systems. Those may not only enable novel anti-infective molecules to reach their targets, but will also improve the bacterial bioavailability of existing anti-infectives. Additionally, there is a need for better infection models that allow studying drug effects on both the bacteria and the host in a relevant manner as needed for rational anti-infective drug development.

Confocal Microscopy

In article number 2300479, Milo S. P. Shaffer and Yuhan Li, introduce the use of confocal microscopy for multi-modal characterization, in-situ reduction, and flexible patterning of graphene oxide films. The patterning capability is demonstrated at a range of length scales down to 500 nm conductive tracks, promising for future applications in electronics devices. The multiple-pass correlative imaging enables real-time monitoring of the reduction mechanism both within single-flakes and across a functional coating.

This study reports an ultrawide-bandgap 2D oxide semiconductor, AsSbO₃, with a highly anisotropic structure. The photodetectors fabricated based on the corresponding nanosheets exhibit excellent selectivity and photoresponse properties for the solar-blind UV (200–280 nm) band. Finally, a simple machine vision system is simulated by combining the device performance with a convolutional neural network.

Abstract

Facing the future development trend of miniaturization and intelligence of electronic devices, solar-blind photodetectors based on ultrawide-bandgap 2D semiconductors have the advantages of low dark current, and high signal-to-noise ratio, as well as the features of micro-nanometer miniaturization and multi-functionalization of 2D material devices, which have potential applications in the photoelectric sensor part of high-performance machine vision systems. This study reports a 2D oxide semiconductor, AsSbO₃, with an ultrawide bandgap (4.997 eV for monolayer and 4.4 eV for multilayer) to be used to fabricate highly selective solar-blind UV photodetectors, of which the dark current as low as 100 fA and rejection ratio of UV-C and UV-A reaches 7.6 × 10³. Under 239 nm incident light, the responsivity is 105 mA W⁻¹ and the detectivity is 7.58 × 10¹² Jones. Owing to the remarkable anisotropic crystal structure, AsSbO₃ also shows significant linear dichroism and nonlinear optical properties. Finally, a simple machine vision system is simulated by combining the real-time imaging function in solar-blind UV with a convolutional neural network. This study enriches the material system of ultrawide-bandgap 2D semiconductors and provides insight into the future development of high-performance solar-blind UV optoelectronic devices.

Nature Nanotechnology, Published online: 27 July 2023; doi:10.1038/s41565-023-01460-w

Using metal–organic chemical vapour deposition, high-crystallinity MoS2 monolayers are grown directly on polymers and thin glass substrates at about 150 °C, thus avoiding any transfer process, preserving the electronic properties of MoS2.

Nature Nanotechnology, Published online: 27 July 2023; doi:10.1038/s41565-023-01457-5

The development of flexible thermoelectrics is limited by the low power factor and brittleness of materials. Here the authors present strategy to turn Bi2Te3-based single crystals into flexible films with staggered-layer structure while maintaining superior thermoelectric performance.

Nature Nanotechnology, Published online: 27 July 2023; doi:10.1038/s41565-023-01464-6

P-type and n-type exfoliated Bi2Te3 thin films show high power generation performance at room temperature for flexible thermoelectric devices.

Nature Communications, Published online: 25 July 2023; doi:10.1038/s41467-023-40172-6

Owing to the nonequilibrium nature, photonic topological phenomena can involve multiple band gaps. Here the authors report on the discovery of a class of hybrid topological photonic crystals that host quantum anomalous Hall and valley Hall phases simultaneously.