Chen

Nature Materials, Published online: 01 June 2023; doi:10.1038/s41563-023-01561-w

Above-bandgap, nanosecond laser pulses enable the localized in situ writing of spin defects in prefabricated nanophotonic cavities. The approach preserves defect and cavity mode properties, key requirements towards cavity–emitter coupling in quantum networks.

The band offsets and the chemical bonding at the interfaces between (-201) $\beta$-Ga$_2$O$_3$ and Al$_2$O$_3$ polymorphs are studied through hybrid functional calculations. For alumina, we consider four representative phases, i.e., $\alpha$, $\kappa$, $\theta$ and $\gamma$-Al$_2$O$_3$. We generate realistic slab models for the interfaces which satisfy electron counting rules. The O atoms bridge the $\beta$-Ga$_2$O$_3$ and Al$_2$O$_3$ slabs and all the dangling bonds are saturated. The band offsets are obtained by applying an alignment scheme which requires separate bulk and interface calculations. The calculated band offsets are useful for the design of devices based on the $\beta$-Ga$_2$O$_3$/Al$_2$O$_3$heterojunctions, particularly $\beta$-Ga$_2$O$_3$ metal-oxide semiconductor field effect transistors.

Author(s): Paulina Majchrzak, Sahar Pakdel, Deepnarayan Biswas, Alfred J. H. Jones, Klara Volckaert, Igor Marković, Federico Andreatta, Raman Sankar, Chris Jozwiak, Eli Rotenberg, Aaron Bostwick, Charlotte E. Sanders, Yu Zhang, Gabriel Karras, Richard T. Chapman, Adam Wyatt, Emma Springate, Jill A. Miwa, Philip Hofmann, Phil D. C. King, Nicola Lanatà, Young Jun Chang, and Søren Ulstrup

We apply an intense infrared laser pulse in order to perturb the electronic and vibrational states in the three-dimensional charge density wave material 1T−VSe2. Ultrafast snapshots of the light-induced hot carrier dynamics and nonequilibrium quasiparticle spectral function are collected using time-...

[Phys. Rev. B 103, L241108] Published Wed Jun 16, 2021

Nature Physics, Published online: 05 October 2020; doi:10.1038/s41567-020-1028-0

Scale-invariant magnetic anisotropy in RuCl3 has been revealed through measurements of its magnetotropic coefficient, providing evidence for a high degree of exchange frustration that favours the formation of a spin liquid state.

Author(s): P. Doležal, M. Kratochvílová, V. Holý, P. Čermák, V. Sechovský, M. Dušek, M. Míšek, T. Chakraborty, Y. Noda, Suhan Son, and Je-Geun Park

The results of a single-crystal x-ray-diffraction study of the evolution of the crystal structures of VI3 with temperature with an emphasis on phase transitions are presented. Some related specific-heat and magnetization data are included. The existence of the room-temperature trigonal crystal struc...

[Phys. Rev. Materials 3, 121401(R)] Published Thu Dec 19, 2019

Viscous phenomena are the hallmark of the hydrodynamic flow exhibited by Dirac fermions in clean graphene at high enough temperatures. We report a quantitative calculation of the electronic shear and Hall viscosities in graphene based on the kinetic theory combined with the renormalization group providing a unified description at arbitrary doping levels and non-quantizing magnetic fields. At charge neutrality, the Hall viscosity vanishes, while the field-dependent shear viscosity decays from its zero-field value saturating to a nonzero value in classically strong fields. Away from charge neutrality, the field-dependent viscosity coefficients tend to agree with the semiclassical expectation.

The ecological drivers of variation in global language diversity

The ecological drivers of variation in global language diversity, Published online: 03 May 2019; doi:10.1038/s41467-019-09842-2

Could similar ecological and biogeographic drivers explain the distributions of biological diversity and human cultural diversity? The authors explore ecological correlates of human language diversity, finding strong support for a role of high year-round productivity but less support for landscape features.

Nature Nanotechnology 11, 465 (2016). doi:10.1038/nnano.2015.323

Authors: Sidong Lei, Xifan Wang, Bo Li, Jiahao Kang, Yongmin He, Antony George, Liehui Ge, Yongji Gong, Pei Dong, Zehua Jin, Gustavo Brunetto, Weibing Chen, Zuan-Tao Lin, Robert Baines, Douglas S. Galvão, Jun Lou, Enrique Barrera, Kaustav Banerjee, Robert Vajtai & Pulickel Ajayan

IV-VI diluted magnetic semiconductor Ge1-xCrxTe layers up to x=0.1 were grown on SrF2 substrates by molecular beam epitaxy. In site reflection high-energy electron diffraction shows a streaky pattern with sixfold symmetry in the plane for the Ge1-xCrxTe layer, implying an epitaxial growth of Ge1-xCrxTe [111]/SrF2 [111]. A clear hysteresis loop is observed in the anomalous Hall effect measurements due to the strong spin-orbit interaction in the host GeTe. The Curie temperature increases with increasing Cr composition up to 200 K, but there is no clear dependence of the Curie temperature on the hole concentration, implying that the mechanism of the ferromagnetic interaction among Cr ions is different from Mn doped diluted magnetic semiconductors.

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Nature advance online publication 06 January 2016. doi:10.1038/nature16475

Authors: Sang Bae Lee, Veronique Frattini, Mukesh Bansal, Angelica M. Castano, Dan Sherman, Keino Hutchinson, Jeffrey N. Bruce, Andrea Califano, Guangchao Liu, Timothy Cardozo, Antonio Iavarone & Anna Lasorella

Article

Bismuth vanadate is a promising photoanode for water-splitting, although its performance is limited by its wide bandgap. Here, the authors show that a gentle nitrogen treatment can result in nitrogen doping and oxygen vacancy generation, simultaneously reducing bandgap and increasing charge transport.

Nature Communications doi: 10.1038/ncomms9769

Authors: Tae Woo Kim, Yuan Ping, Giulia A. Galli, Kyoung-Shin Choi

The representative measurements of the second harmonic in ac magnetization complemented by neutron depolarization have been performed for single-crystal La0.85Sr0.15CoO3 in the temperature range 97 K < T < 230 K, where occurrence of a small fraction (~ 0.001) of nanoscale ferromagnetic clusters (FMC) has been found. Magnetic, geometrical and dynamical parameters of the FMC system have been evaluated in the temperature range T < 140 K, where superparamagnetic regime installs, by means of the formalism involving the Fokker-Planck equation (FPE). With lowering the temperature, the amount of clusters fraction, the cluster size and magnetic moment along with its diffusion relaxation time strongly increase, each in its own temperature interval. Below 130 K, FMC contribute essentially to the total linear magnetic susceptibility. The damping factor of the order 0.1 proves the importance of precession in thermal relaxation of the cluster magnetic moment. The FMC are a precursor of long-range ferromagnetic correlations seen below 100 K with neutron-scattering techniques. The employed technique supplemented with FPE-based data-treatment formalism is a novel method for studying superparamagnetic systems.

Author(s): Shuji Sakabe, Masaki Hashida, Shigeki Tokita, Shin Namba, and Kiminori Okamuro

[Phys. Rev. B 91, 159902] Published Tue Apr 07, 2015