05 Apr 02:18
by Jiangjiang Feng,
Xiaohui Li,
Zhaojiang Shi,
Chuang Zheng,
Xuwei Li,
Deying Leng,
Yamin Wang,
Jie Liu,
Lujun Zhu
As a member of the 2D transition metal chalcogenides (TMCs), 2D Ag2S with large absorption coefficient, broadband optical response, and unique layered structure has offered a platform for achieving tremendous success in various fields. Herein, an Ag2S saturable absorber (SA) is incorporated into an Er‐doped fiber laser to achieve a 229th harmonic soliton molecule, corresponding to a repetition frequency of 1.1 GHz for the first time.
Abstract
As a member of the 2D transition metal chalcogenides (TMCs), 2D Ag2S with large absorption coefficient, broadband optical response, extraordinary metal‐like ductility, high plastic deformation strain, unique layered structure, and very low solubility has offered a platform for achieving tremendous success in various fields. Great achievements have been made in exploring the linear optical, mechanical, and photoelectric properties of 2D Ag2S nanosheets. However, the nonlinear optical properties of 2D Ag2S nanosheets and their applications in ultrafast photonics have not been studied. The saturable absorption property of 2D Ag2S nanosheets is experimentally illustrated at the telecommunication band with a large optical modulation depth of 15.5% and a low saturable intensity of 250.4 MW cm−2. Moreover, the 229th harmonic soliton molecule with repetition rate of 1.1 GHz based on 2D Ag2S saturable absorber is realized at the telecommunication band for the first time to the authors' knowledge. Thankfully, 2D Ag2S nanosheets display excellent nonlinear optical properties suggesting that this may open a new door for advanced photonic devices based on 2D Ag2S nanosheets.
05 Apr 02:17
by Shuangyan Liu,
Congwei Tan,
Dawei He,
Yongsheng Wang,
Hailin Peng,
Hui Zhao
Here, an optical study of Bi2O2Se, an emerging 2D semiconductor, is reported. Steady‐state spectroscopic tools and transient absorption technique are used to study various optical properties of monolayers and nanoplates of Bi2O2Se. Information about the direct bandgap, absorption coefficient, photocarrier lifetime, and diffusion coefficient is obtained. These results help develop photonic and optoelectronic applications based on this material.
Abstract
A comprehensive experimental study on optical properties and photocarrier dynamics in Bi2O2Se monolayers and nanoplates is presented. Large and uniform Bi2O2Se nanoplates with various thicknesses down to the monolayer limit are fabricated. In nanoplates, a direct optical transition near 720 nm is identified by optical transmission, photoluminescence, and transient absorption spectroscopic measurements and is attributed to the transition between the valence and conduction bands in the Γ valley. Time‐resolved differential reflection measurements reveal ultrafast carrier thermalization and energy relaxation processes and a photocarrier recombination lifetime of about 200 ps in nanoplates. Furthermore, by spatially resolving the differential reflection signal, a photocarrier diffusion coefficient of about 4.8 cm2 s−1 is obtained, corresponding to a mobility of about 180 cm2 V−1 s−1. A similar direct transition is also observed in monolayer Bi2O2Se, suggesting that the states in the Γ valley do not change significantly with the thickness. The temporal dynamics of the excitons in the monolayer is quite different from the nanoplates, with a strong saturation effect and fast exciton–exciton annihilation at high densities. Spatially and temporally resolved measurements yield an exciton diffusion coefficient of about 20 cm2 s−1.
05 Apr 02:14
by Tianyi Zhang†‡, Kazunori Fujisawa‡§?, Fu Zhang†‡, Mingzu Liu‡§, Michael C. Lucking?, Rafael Nunes Gontijo§, Yu Lei‡§, He Liu‡#, Kevin Crust§, Tomotaroh Granzier-Nakajima‡§, Humberto Terrones?, Ana Laura Eli´as*‡§, and Mauricio Terrones*†‡§#
ACS Nano
DOI: 10.1021/acsnano.9b09857
05 Apr 02:14
by Ulrich Ngue´tchuissi Noumbe´†?, Charlie Gre´boval‡?, Cle´ment Livache‡, Audrey Chu‡, Hicham Majjad†, Luis E. Parra Lo´pez†, Louis Donald Notemgnou Mouafo†, Bernard Doudin†, Ste´phane Berciaud†§, Julien Chaste?, Abdelkarim Ouerghi?, Emmanuel Lhuillier*‡, and Jean-Francois Dayen*†§
ACS Nano
DOI: 10.1021/acsnano.0c00103
05 Apr 02:13
by Michael F. Mazza†‡, Miguel Caba´n-Acevedo†‡, Joshua D. Wiensch†, Annelise C. Thompson†, and Nathan S. Lewis*†
Nano Letters
DOI: 10.1021/acs.nanolett.0c00179
05 Apr 02:12
by Hailang Qin†, Bin Guo†, Linjing Wang†, Meng Zhang†, Bochao Xu†, Kaige Shi†, Tianluo Pan†, Liang Zhou†, Junshu Chen†, Yang Qiu‡, Bin Xi§, Iam Keong Sou||, Dapeng Yu†, Wei-Qiang Chen†, Hongtao He*†, Fei Ye*†, Jia-Wei Mei*†, and Gan Wang*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b05167
05 Apr 02:12
by Manfred Ersfeld†#, Frank Volmer†#, Lars Rathmann†#, Luca Kotewitz†, Maximilian Heithoff†, Mark Lohmann‡, Bowen Yang¶, Kenji Watanabe§, Takashi Taniguchi§, Ludwig Bartels¶, Jing Shi‡, Christoph Stampfer†||, and Bernd Beschoten*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b05138
05 Apr 02:11
by Sai S. Sunku†‡?, Alexander S. McLeod†?, Tobias Stauber§, Hyobin Yoo?, Dorri Halbertal†, Guangxin Ni†, Aaron Sternbach†, Bor-Yuan Jiang?, Takashi Taniguchi#, Kenji Watanabe#, Philip Kim?, Michael M. Fogler?, and D. N. Basov*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b04637
05 Apr 02:08
by Yi‐Zhou Zhang,
Yang Wang,
Qiu Jiang,
Jehad K. El‐Demellawi,
Hyunho Kim,
Husam N. Alshareef
Recent progress in the deposition/patterning of MXenes through printing and coating methods is summarized, including issues that are related to the formulation of MXene inks (e.g., dispersion, stability, and tuning of physical–chemical and morphological properties), relevant printing/coating methods, and their applications in energy storage, electronics/optoelectronics, sensing, and actuation.
Abstract
As a thriving member of the 2D nanomaterials family, MXenes, i.e., transition metal carbides, nitrides, and carbonitrides, exhibit outstanding electrochemical, electronic, optical, and mechanical properties. They have been exploited in many applications including energy storage, electronics, optoelectronics, biomedicine, sensors, and catalysis. Compared to other 2D materials, MXenes possess a unique set of properties such as high metallic conductivity, excellent dispersion quality, negative surface charge, and hydrophilicity, making them particularly suitable as inks for printing applications. Printing and pre/post‐patterned coating methods represent a whole range of simple, economically efficient, versatile, and eco‐friendly manufacturing techniques for devices based on MXenes. Moreover, printing can allow for complex 3D architectures and multifunctionality that are highly required in various applications. By means of printing and patterned coating, the performance and application range of MXenes can be dramatically increased through careful patterning in three dimensions; thus, printing/coating is not only a device fabrication tool but also an enabling tool for new applications as well as for industrialization.
05 Apr 02:05
by Kai Qian,
Lei Gao,
Xiya Chen,
Hang Li,
Shuai Zhang,
Xian‐Li Zhang,
Shiyu Zhu,
Jiahao Yan,
Deliang Bao,
Lu Cao,
Jin‐An Shi,
Jianchen Lu,
Chen Liu,
Jiaou Wang,
Tian Qian,
Hong Ding,
Lin Gu,
Wu Zhou,
Yu‐Yang Zhang,
Xiao Lin,
Shixuan Du,
Min Ouyang,
Sokrates T. Pantelides,
Hong‐Jun Gao
Purely thermal, stoichiometry‐preserving, structural phase transitions are common in bulk materials, but have not been observed in 2D materials. The fabrication of monolayer Cu2Se, a new air‐stable 2D material, is reported, demonstrating the existence of purely thermal, stoichiometry‐preserving, reversible phase transitions with a critical temperature of ≈147 K.
Abstract
Materials possessing structural phase transformations exhibit a rich set of physical and chemical properties that can be used for a variety of applications. In 2D materials, structural transformations have so far been induced by strain, lasers, electron injection, electron/ion beams, thermal loss of stoichiometry, and chemical treatments or by a combination of such approaches and annealing. However, stoichiometry‐preserving, purely thermal, reversible phase transitions, which are fundamental in physics and can be easily induced, have not been observed. Here, the fabrication of monolayer Cu2Se, a new 2D material is reported, demonstrating the existence of a purely thermal structural phase transition. Scanning tunneling microscopy, scanning transmission electron microscopy, and density functional theory (DFT) identify two structural phases at 78 and 300 K. DFT calculations trace the phase‐transition mechanism via the existence/absence of imaginary (unstable) phonon modes at low and high temperatures. In situ, variable‐temperature low‐energy electron diffraction patterns demonstrate that the phase transition occurs across the whole sample at ≈147 K. Angle‐resolved photoemission spectra and DFT calculations show that a degeneracy at the Γ point of the energy bands of the high‐temperature phase is lifted in the low‐temperature phase. This work opens up possibilities for studying such phase transitions in 2D materials.
05 Apr 02:05
by Yuda Zhao,
Simone Bertolazzi,
Maria Serena Maglione,
Concepció Rovira,
Marta Mas‐Torrent,
Paolo Samorì
An ionic‐liquid‐gated two‐dimensional MoS2 field‐effect transistor with the functionalization of ferrocene‐substituted alkanethiol molecules is fabricated. It can in situ program and sense the electrochemical state of adsorbed redox‐active molecules. The electrochemical stimuli from the redox‐active molecules represent a remote control to modulate the electrical transport of monolayer MoS2.
Abstract
As Moore's law is running to its physical limit, tomorrow's electronic systems can be leveraged to a higher value by integrating “More than Moore” technologies into CMOS digital circuits. The hybrid heterostructure composed of two‐dimensional (2D) semiconductors and molecular materials represents a powerful strategy to confer new properties to the former components, realize stimuli‐responsive functional devices, and enable diversification in “More than Moore” technologies. Here, an ionic liquid (IL) gated 2D MoS2 field‐effect transistor (FET) with molecular functionalization is fabricated. The suitably designed ferrocene‐substituted alkanethiol molecules not only improve the FET performance, but also show reversible electrochemical switching on the surface of MoS2. Field‐effect mobility of monolayer MoS2 reaches values as high as ≈116 cm2 V−1 s−1 with I
on/I
off ratio exceeding 105. Molecules in their neutral or charged state impose distinct doping effect, efficiently tuning the electron density in monolayer MoS2. It is noteworthy that the joint doping effect from IL and switchable molecules results in the steep subthreshold swing of MoS2 FET in the backward sweep. These results demonstrate that the device architecture represents an unprecedented and powerful strategy to fabricate switchable 2D FET with a chemically programmed electrochemical signal as a remote control, paving the road toward novel functional devices.
05 Apr 02:04
by Gyoung Hwa Jeong,
Suchithra Padmajan Sasikala,
Taeyeong Yun,
Gil Yong Lee,
Won Jun Lee,
Sang Ouk Kim
Nanoscale assembly—the precise control over the complex interface between layers—is essential to promote continuous progress of 2D materials, especially in energy storage and conversion and environmental remediation. Recent progress, the status, future prospects, and challenges facing the nanoscopic assembly of 2D materials, mainly for energy and environmental applications, are discussed.
Abstract
Rational design of 2D materials is crucial for the realization of their profound implications in energy and environmental fields. The past decade has witnessed significant developments in 2D material research, yet a number of critical challenges remain for real‐world applications. Nanoscale assembly, precise control over the orientational and positional ordering, and complex interfaces among 2D layers are essential for the continued progress of 2D materials, especially for energy storage and conversion and environmental remediation. Herein, recent progress, the status, future prospects, and challenges associated with nanoscopic assembly of 2D materials are highlighted, specifically targeting energy and environmental applications. Geometric dimensional diversity of 2D material assembly is focused on, based on novel assembly mechanisms, including 1D fibers from the colloidal liquid crystalline phase, 2D films by interfacial tension (Marangoni effect), and 3D nanoarchitecture assembly by electrochemical processes. Relevant critical advantages of 2D material assembly are highlighted for application fields, including secondary batteries, supercapacitors, catalysts, gas sensors, desalination, and water decontamination.
28 Mar 06:11
by Alex C. Schilling†, Andrew J. Therrien†, Ryan T. Hannagan†, Matthew D. Marcinkowski†, Paul L. Kress†, Dipna A. Patel†, Tedros A. Balema†, Amanda M. Larson†, Felicia R. Lucci†, Benjamin P. Coughlin†, Renqin Zhang‡, Theodore Thuening†, Volkan C¸inar†, Jean-Sabin McEwen‡§??#, Andrew J. Gellman¶?, and E. Charles H. Sykes*†
ACS Nano
DOI: 10.1021/acsnano.0c00398
28 Mar 06:10
by Jaehoon Ji†, Charles M. Delehey†, Duncan N. Houpt†, Mathew K. Heighway†, Tonghun Lee‡, and Jong Hyun Choi*†
Nano Letters
DOI: 10.1021/acs.nanolett.9b05254
28 Mar 06:10
by Kyrylo Greben*, Sonakshi Arora†, Moshe G. Harats, and Kirill I. Bolotin*
Nano Letters
DOI: 10.1021/acs.nanolett.9b05323
28 Mar 06:09
by Wenda Zhou†‡?, Mingyue Chen†?, Manman Guo†, Aijun Hong†, Ting Yu†, Xingfang Luo†, Cailei Yuan*†, Wen Lei§, and Shouguo Wang*‡
Nano Letters
DOI: 10.1021/acs.nanolett.0c00845
28 Mar 06:09
by Jinshui Miao†, Xiwen Liu†, Kiyoung Jo†, Kang He?, Ravindra Saxena†, Baokun Song†, Huiqin Zhang†, Jiale He‡, Myung-Geun Han§, Weida Hu‡, and Deep Jariwala*†
Nano Letters
DOI: 10.1021/acs.nanolett.0c00741
28 Mar 06:04
Nanoscale, 2020, 12,8371-8378
DOI: 10.1039/C9NR10383J, Paper
Manabendra Kuiri, Subhadip Das, D. V. S. Muthu, Anindya Das, A. K. Sood
The resistivity of the semiconducting ultra-thin 1T′-MoTe2 shows a clear signature of temperature induced transition to Weyl semimetallic Td phase. Resistivity upturn at low temperature (∼20 K) confirms electron–electron interaction physics at the Weyl nodes.
The content of this RSS Feed (c) The Royal Society of Chemistry
22 Mar 03:50
by Tun Cao,
Kuan Liu,
Li Lu,
Jianxun Liu,
Yan Jun Liu,
Kai Rong Qin,
Hsiang Chen Chui,
Robert E. Simpson
The employment of Au nanoparticles (NPs) can significantly reduce operation power and time necessary to reach the temperature for Ge2Sb2Te5 (GST) crystallization and reamorphization. This is due to the enhanced light absorptance through strongly localised surface plasmon resonances of Au NPs. It indicates that the GST film–Au NP system is suitable for high‐speed and low‐power phase change memory.
Abstract
Chalcogenide materials are attractive for all‐photonic phase‐change memories owing to their large optical contrast between amorphous and crystalline structural phases. However, high‐power heating pulses are required to switch these structural phases, which can limit the cyclability. To reduce power, Au nanoparticles (NPs) are embedded in a typical chalcogenide phase‐change material, Ge2Sb2Te5 (GST). Raman analysis shows that a GST film crystallizes at a low optical power of 2 mW, which is almost 10 times lower than that of materials not embedded with NPs. This lower power is owing to the enhanced light absorptance through the strongly localized surface plasmon resonance (LSPR) of the Au NPs. The Au NPs embedded in the GST film scatter light at λ = 587 nm, which is close to Au NP's LSPR of ≈535 nm. Laser light at 532 nm is used to measure Raman scattering from the Au–GST system. The Raman scattering is enhanced by a factor 12 compared with a bare GST film. This study indicates that the GST film–Au NP system is suitable for high‐speed, low‐power, phase‐change memory and for a new type of tunable surface‐enhanced Raman scattering substrate.
22 Mar 03:49
by Jiangjiang Feng,
Xiaohui Li,
Zhaojiang Shi,
Chuang Zheng,
Xuwei Li,
Deying Leng,
Yamin Wang,
Jie Liu,
Lujun Zhu
As a member of the 2D transition metal chalcogenides (TMCs), 2D Ag2S with large absorption coefficient, broadband optical response, and unique layered structure has offered a platform for achieving tremendous success in various fields. Herein, an Ag2S saturable absorber (SA) is incorporated into an Er‐doped fiber laser to achieve a 229th harmonic soliton molecule, corresponding to a repetition frequency of 1.1 GHz for the first time.
Abstract
As a member of the 2D transition metal chalcogenides (TMCs), 2D Ag2S with large absorption coefficient, broadband optical response, extraordinary metal‐like ductility, high plastic deformation strain, unique layered structure, and very low solubility has offered a platform for achieving tremendous success in various fields. Great achievements have been made in exploring the linear optical, mechanical, and photoelectric properties of 2D Ag2S nanosheets. However, the nonlinear optical properties of 2D Ag2S nanosheets and their applications in ultrafast photonics have not been studied. The saturable absorption property of 2D Ag2S nanosheets is experimentally illustrated at the telecommunication band with a large optical modulation depth of 15.5% and a low saturable intensity of 250.4 MW cm−2. Moreover, the 229th harmonic soliton molecule with repetition rate of 1.1 GHz based on 2D Ag2S saturable absorber is realized at the telecommunication band for the first time to the authors' knowledge. Thankfully, 2D Ag2S nanosheets display excellent nonlinear optical properties suggesting that this may open a new door for advanced photonic devices based on 2D Ag2S nanosheets.
22 Mar 03:48
by Shuangyan Liu,
Congwei Tan,
Dawei He,
Yongsheng Wang,
Hailin Peng,
Hui Zhao
Here, an optical study of Bi2O2Se, an emerging 2D semiconductor, is reported. Steady‐state spectroscopic tools and transient absorption technique are used to study various optical properties of monolayers and nanoplates of Bi2O2Se. Information about the direct bandgap, absorption coefficient, photocarrier lifetime, and diffusion coefficient is obtained. These results help develop photonic and optoelectronic applications based on this material.
Abstract
A comprehensive experimental study on optical properties and photocarrier dynamics in Bi2O2Se monolayers and nanoplates is presented. Large and uniform Bi2O2Se nanoplates with various thicknesses down to the monolayer limit are fabricated. In nanoplates, a direct optical transition near 720 nm is identified by optical transmission, photoluminescence, and transient absorption spectroscopic measurements and is attributed to the transition between the valence and conduction bands in the Γ valley. Time‐resolved differential reflection measurements reveal ultrafast carrier thermalization and energy relaxation processes and a photocarrier recombination lifetime of about 200 ps in nanoplates. Furthermore, by spatially resolving the differential reflection signal, a photocarrier diffusion coefficient of about 4.8 cm2 s−1 is obtained, corresponding to a mobility of about 180 cm2 V−1 s−1. A similar direct transition is also observed in monolayer Bi2O2Se, suggesting that the states in the Γ valley do not change significantly with the thickness. The temporal dynamics of the excitons in the monolayer is quite different from the nanoplates, with a strong saturation effect and fast exciton–exciton annihilation at high densities. Spatially and temporally resolved measurements yield an exciton diffusion coefficient of about 20 cm2 s−1.
22 Mar 03:47
by Kazeto Morisawa, Takuya Ishida, and Tetsu Tatsuma*
ACS Nano
DOI: 10.1021/acsnano.9b10216
22 Mar 03:47
by Mengji Chen†?, Kyusup Lee†?, Jie Li‡, Liang Cheng§, Qisheng Wang†, Kaiming Cai†, Elbert E. M. Chia§, Haixin Chang‡, and Hyunsoo Yang*†
ACS Nano
DOI: 10.1021/acsnano.9b09828
22 Mar 03:46
by Yu-Chuan Lin†, Chenze Liu‡, Yiling Yu†, Eva Zarkadoula§, Mina Yoon†, Alexander A. Puretzky†, Liangbo Liang†, Xiangru Kong†, Yiyi Gu‡?, Alex Strasser†?, Harry M. Meyer III†, Matthias Lorenz†, Matthew F. Chisholm†, Ilia N. Ivanov†, Christopher M. Rouleau†, Gerd Duscher‡, Kai Xiao†, and David B. Geohegan*†
ACS Nano
DOI: 10.1021/acsnano.9b10196
22 Mar 03:46
by Qi Li†?, Xiaoxu Zhao‡?, Longjiang Deng†, Zhongtai Shi†, Sheng Liu?, Qilin Wei?, Linbo Zhang†, Yingchun Cheng*?, Li Zhang†, Haipeng Lu†, Weibo Gao?, Wei Huang?, Cheng-Wei Qiu¶, Gang Xiang#, Stephen John Pennycook‡, Qihua Xiong?, Kian Ping Loh*§, and Bo Peng*†
ACS Nano
DOI: 10.1021/acsnano.0c00291
22 Mar 03:44
by Matthew R. Rosenberger*†§, Hsun-Jen Chuang†§, Madeleine Phillips†, Vladimir P. Oleshko‡, Kathleen M. McCreary†, Saujan V. Sivaram†, C. Stephen Hellberg†, and Berend T. Jonker†
ACS Nano
DOI: 10.1021/acsnano.0c00088
22 Mar 03:43
by Jianbo Sun†, Giacomo Giorgi‡§, Maurizia Palummo??, Peter Sutter#, Maurizio Passacantando??, and Luca Camilli*†?
ACS Nano
DOI: 10.1021/acsnano.0c00836
22 Mar 03:41
by Wan-Ping Guo†, Wei-Yun Liang‡, Chang-Wei Cheng§, Wei-Lin Wu§, Yen-Ting Wang?|, Quan Sun#, Shuai Zu#, Hiroaki Misawa#?, Pi-Ju Cheng?, Shu-Wei Chang?, Hyeyoung Ahn*‡, Minn-Tsong Lin*†?, and Shangjr Gwo*§??|
Nano Letters
DOI: 10.1021/acs.nanolett.0c00645
22 Mar 03:34
by Yiyi Gu,
Hui Cai,
Jichen Dong,
Yiling Yu,
Anna N. Hoffman,
Chenze Liu,
Akinola D. Oyedele,
Yu‐Chuan Lin,
Zhuozhi Ge,
Alexander A. Puretzky,
Gerd Duscher,
Matthew F. Chisholm,
Philip D. Rack,
Christopher M. Rouleau,
Zheng Gai,
Xiangmin Meng,
Feng Ding,
David B. Geohegan,
Kai Xiao
Highly anisotropic pentagonal 2D PdSe2 is synthesized by a chemical vapor deposition method, exhibiting a high electron mobility up to ≈294 cm2 V−1 s−1 and strong in‐plane optical anisotropy.
Abstract
Two‐dimensional (2D) palladium diselenide (PdSe2) has strong interlayer coupling and a puckered pentagonal structure, leading to remarkable layer‐dependent electronic structures and highly anisotropic in‐plane optical and electronic properties. However, the lack of high‐quality, 2D PdSe2 crystals grown by bottom‐up approaches limits the study of their exotic properties and practical applications. In this work, chemical vapor deposition growth of highly crystalline few‐layer (≥2 layers) PdSe2 crystals on various substrates is reported. The high quality of the PdSe2 crystals is confirmed by low‐frequency Raman spectroscopy, scanning transmission electron microscopy, and electrical characterization. In addition, strong in‐plane optical anisotropy is demonstrated via polarized Raman spectroscopy and second‐harmonic generation maps of the PdSe2 flakes. A theoretical model based on kinetic Wulff construction theory and density functional theory calculations is developed and described the observed evolution of “square‐like” shaped PdSe2 crystals into rhombus due to the higher nucleation barriers for stable attachment on the (1,1) and (1,−1) edges, which results in their slower growth rates. Few‐layer PdSe2 field‐effect transistors reveal tunable ambipolar charge carrier conduction with an electron mobility up to ≈294 cm2 V−1 s−1, which is comparable to that of exfoliated PdSe2, indicating the promise of this anisotropic 2D material for electronics.
22 Mar 03:33
by Hongjun Xu,
Jinwu Wei,
Hengan Zhou,
Jiafeng Feng,
Teng Xu,
Haifeng Du,
Congli He,
Yuan Huang,
Junwei Zhang,
Yizhou Liu,
Han‐Chun Wu,
Chenyang Guo,
Xiao Wang,
Yao Guang,
Hongxiang Wei,
Yong Peng,
Wanjun Jiang,
Guoqiang Yu,
Xiufeng Han
PtTe2, a layered type‐II Dirac semimetal, is successfully synthesized in a scalable and controllable manner. High spin–orbit torque and large spin Hall conductivity are found in these PtTe2 thin films, which manifest the potential of PtTe2 thin film for energy‐efficient magnetization switching. The experiments establish a primary basis for further research on similar systems for high‐performance spintronic devices.
Abstract
Manipulation of magnetization by electric‐current‐induced spin–orbit torque (SOT) is of great importance for spintronic applications because of its merits in energy‐efficient and high‐speed operation. An ideal material for SOT applications should possess high charge‐spin conversion efficiency and high electrical conductivity. Recently, transition metal dichalcogenides (TMDs) emerge as intriguing platforms for SOT study because of their controllability in spin–orbit coupling, conductivity, and energy band topology. Although TMDs show great potentials in SOT applications, the present study is restricted to the mechanically exfoliated samples with small sizes and relatively low conductivities. Here, a manufacturable recipe is developed to fabricate large‐area thin films of PtTe2, a type‐II Dirac semimetal, to study their capability of generating SOT. Large SOT efficiency together with high conductivity results in a giant spin Hall conductivity of PtTe2 thin films, which is the largest value among the presently reported TMDs. It is further demonstrated that the SOT from PtTe2 layer can switch a perpendicularly magnetized CoTb layer efficiently. This work paves the way for employing PtTe2‐like TMDs for wafer‐scale spintronic device applications.
