Article
Physics, Multidisciplinary
P. O. Sukhachov, L. Glazman
Summary: The response of a Weyl or Dirac semimetal to an electromagnetic field becomes nonlocal due to the activation of chiral anomaly by a static magnetic field. This nonlocality is developed under the conditions of the normal skin effect and is related to the imbalance in valley charge caused by the joint effect of the impinging wave's electric field and the static magnetic field. We elucidate the signatures of this nonlocality in the transmission of electromagnetic waves, including the enhancement of transmission amplitude and its specific dependence on the frequency and magnetic field strength.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Nicholas R. Poniatowski, Tarapada Sarkar, Richard L. Greene
Summary: The magnetoresistance and Hall angle measurements of the electron-doped cuprate La2-xCexCuO4 show unconventional behavior over a wide doping range, with different dependencies and temperature changes noted in samples with varying dopings.
Article
Multidisciplinary Sciences
Masaki Uchida, Shin Sato, Hiroaki Ishizuka, Ryosuke Kurihara, Taro Nakajima, Yusuke Nakazawa, Mizuki Ohno, Markus Kriener, Atsushi Miyake, Kazuki Ohishi, Toshiaki Morikawa, Mohammad Saeed Bahramy, Taka-hisa Arima, Masashi Tokunaga, Naoto Nagaosa, Masashi Kawasaki
Summary: The study of the magnetic semiconductor EuAs revealed a new mechanism for inducing large anomalous Hall effect (AHE) in magnetic semiconductors through spin cluster scattering. This suggests potential for developing a field targeting diluted carriers strongly coupled to noncoplanar spin structures.
Article
Materials Science, Multidisciplinary
P. O. Sukhachov, Bjoern Trauzettel
Summary: The role of the chiral anomaly in the hydrodynamic and crossover regimes of transport in Weyl or Dirac semimetal films has been investigated. It was shown that the electric conductivity in the direction of the magnetic field exhibits an unusual nonmonotonic dependence on temperature, referred to as the anomalous Gurzhi effect. This effect occurs in clean semimetals under a weak magnetic field, with electron-electron scattering dominating and relaxation of valley-imbalance charge density occurring at the boundaries. Additionally, the conditions for the conventional Gurzhi effect in hydrodynamic and crossover transport regimes in three-dimensional Dirac and Weyl semimetals have been determined.
Article
Optics
Xiaohui Ling, Weilai Xiao, Shizhen Chen, Xinxing Zhou, Hailu Luo, Lei Zhou
Summary: The study reanalyzes the optical spin-Hall effect using rigorous calculations and the Berry phase concept, revealing the spin-flipped abnormal mode and spin-maintained normal mode generated when circularly and linearly polarized light beams strike an optical interface, leading to spin-Hall shifts.
Review
Nanoscience & Nanotechnology
Libor Smejkal, Allan H. MacDonald, Jairo Sinova, Satoru Nakatsuji, Tomas Jungwirth
Summary: This review organizes the current understanding of anomalous antiferromagnetic materials that generate a Hall effect and discusses their applications in spintronics, topological condensed matter, and multipole magnetism.
NATURE REVIEWS MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Lijuan Qian, Shiyu Zhou, Kang Wang, Gang Xiao
Summary: The study reveals that in a one-dimensional half-metallic CrO2 nanoscale conductor, the magnetoresistance induced by a single magnetic domain wall is enhanced by 70 fold when the channel width decreases from 200 nm to 30 nm, due to the increased domain wall resistance and additional contribution of ballistic magnetoresistance. The research predicts that a simple CrO2 nanowire impregnated with a constriction at a 150 nm(2) cross-section could achieve a magnetoresistance ratio of 100%, far exceeding that of a conventional ferromagnetic nanowire.
Article
Chemistry, Physical
Sumana Kumar, Sukanta Nandi, Vikash Mishra, Alok Shukla, Abha Misra
Summary: In this study, titanium sesquioxide (Ti2O3) is found to exhibit an anomalous increase in its solid-state electrochemical capacitance at high temperatures and an enhancement in its electrochemical capacitance upon infrared illumination at room temperature. This opens up new possibilities for engineering the electrochemical capacitance of Ti2O3.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Materials Science, Multidisciplinary
Huan-Wen Wang, Bo Fu, Shun-Qing Shen
Summary: In this study, the anomalous Hall effect in nonmagnetic transition metal pentatellurides ZrTe5 and HfTe5 is theoretically investigated. It is found that the intrinsic anomalous Hall conductivity induced by the Berry curvature occurs in the presence of Zeeman splitting and Dirac mass in the semiclassical treatment. The decay and vanishing of the anomalous Hall conductivity under constant spin splitting and magnetic-field-dependent Zeeman energy are observed in a finite magnetic field. A semiclassical formula is derived to describe the magnetic field dependence of the Hall conductivity, which is useful for experimental data analysis. Furthermore, a plateau in the Hall conductivity emerges when the chemical potential is fixed in the magnetic field, which could explain the observed anomalous Hall effect in experiments.
Article
Multidisciplinary Sciences
Yunhe Bai, Yuanzhao Li, Jianli Luan, Ruixuan Liu, Wenyu Song, Yang Chen, Peng-Fei Ji, Qinghua Zhang, Fanqi Meng, Bingbing Tong, Lin Li, Yuying Jiang, Zongwei Gao, Lin Gu, Jinsong Zhang, Yayu Wang, Qi-Kun Xue, Ke He, Yang Feng, Xiao Feng
Summary: This study realized quantized anomalous Hall resistivity in MBE-grown MnBi2Te4 thin films by controlling the chemical potential and top gating. Post-annealing can increase the temperature for quantization but also increase the residual longitudinal resistivity.
NATIONAL SCIENCE REVIEW
(2023)
Article
Multidisciplinary Sciences
Yang Li, Shengnan Xu, Jianfeng Wang, Chong Wang, Baishun Yang, Haiqing Lin, Wenhui Duan, Bing Huang
Summary: The coexistence of the quantum anomalous Hall effect (QAHE) and magnetic skyrmion (SK) can generate a previously unknown SK state called the RK joint topological skyrmion. This state allows tunability of the number and chirality of chiral boundary states (CBS) under external fields, providing additional degrees of freedom for manipulation. Furthermore, external fields can induce a continuous topology phase transition from K-space QAHE to R-space SK, serving as an ideal platform to understand crossover phenomena of multiple-space topologies.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Materials Science, Multidisciplinary
Weiwei Wu, Jinfeng Li, Zhiyu Liao, Hongyu Jiang, Laiquan Shen, Lin Gu, Xianggang Qiu, Yugui Yao, Haiyang Bai
Summary: The study reveals the linear dependence of anomalous Hall conductivity on magnetization in ferromagnetic metallic glasses, which indicates intrinsic mechanism contribution. Additionally, the influence of Berry curvature density and spin orientation fluctuations on the anomalous Hall effect is also highlighted.
Article
Chemistry, Multidisciplinary
Toby Nonnenmacher, Titus-Stefan Dascalu, Robert Bingham, Chung Lim Cheung, Hin-Tung Lau, Ken Long, Jurgen Pozimski, Colin Whyte
Summary: The electron plasma lens is a cost-effective and compact focusing element that can efficiently capture low-energy proton and ion beams from laser-driven sources. Experimental results show that the lens can convert pencil beams into rings with position-dependent shape and intensity modulation, suggesting an off-axis rotation similar to the m=1 diocotron instability in the plasma column.
APPLIED SCIENCES-BASEL
(2021)
Article
Geochemistry & Geophysics
S. Saxena, A. Pommier, M. J. Tauber
Summary: Electrical measurements of xenoliths and metal sulfides from Tanzania suggest that low-resistivity anomalies in the lithospheric mantle of cratonic regions can be explained by the presence of solid sulfide. The addition of different volume percentages of FeS has a significant impact on resistivity levels in the samples.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Mathematics
Eugenio Megias, Jose A. S. Lima, Airton Deppman
Summary: This article investigates the source term problem of the nonextensive transport equation and shows through a simple system that nonadditivity is a result of phase space topology.
Article
Physics, Fluids & Plasmas
Xu Chu, P. H. Diamonds, Zhibin Guo
Summary: The pedestal turbulence intensity required to convert the thin, laminar H-mode scrape-off layer (SOL) to a broad turbulent SOL is calculated using the theory of turbulence spreading. A lower bound on the pedestal turbulence level to exceed the neoclassical heuristic drift (HD) width is derived. The study considers both drift wave and ballooning mode turbulence, and finds that the key competition is between spreading and linear E x B shear damping. The required pedestal turbulence levels scale with rho/R.
Article
Physics, Fluids & Plasmas
Chang-Chun Chen, P. H. Diamond, S. M. Tobias
Summary: This paper presents a theory of turbulent transport of parallel momentum and ion heat through the interaction of stochastic magnetic fields and turbulence. It focuses on determining the kinetic stress and the compressive energy flux. A critical parameter, the ratio of turbulent scattering rate to parallel acoustic dispersion rate, is identified. The paper predicts that the relevant form of kinetic stress in practice is the viscous stress, and the quasilinear limit is not observable.
PLASMA PHYSICS AND CONTROLLED FUSION
(2022)
Article
Physics, Fluids & Plasmas
Mingyun Cao, P. H. Diamond
Summary: This paper presents an analysis of instability dynamics in a stochastic magnetic field for the resistive interchange. The externally prescribed static magnetic perturbations convert the eigenmode problem to a stochastic differential equation, which is solved using the method of averaging. The dynamics become multi-scale due to the difference in size between the test mode and magnetic perturbations. The study finds that maintaining quasi-neutrality at all orders requires small-scale convective cell turbulence driven by disparate scale interaction, and the cells in turn produce turbulent mixing of vorticity and pressure.
PLASMA PHYSICS AND CONTROLLED FUSION
(2022)
Article
Physics, Fluids & Plasmas
R. Ke, P. H. Diamond, T. Long, M. Xu, Z. P. Chen, L. Gao, Q. H. Yang, Y. H. Wang, X. Y. Zhang, L. Nie, T. Wu, J. M. Gao, D. Li, N. C. Wang, Z. J. Yang, Z. Y. Chen, Y. Pan, X. R. Duan
Summary: By using a biased electrode, the edge shear layer in high density discharges was sustained, resulting in a stable increase in line-averaged density and edge density, as well as decreased turbulence spreading and particle and heat flux levels, and increased electron adiabaticity.
Editorial Material
Multidisciplinary Sciences
Patrick H. Diamond, Rameswar Singh, Ting Long, Rongjie Hong, Rui Ke, Zheng Yan, Mingyun Cao, George R. Tynan
Summary: The electric field profile structure, especially its shear, is an order parameter for the edge plasma that characterizes different confinement regimes. The theoretical developments and lessons learned from H-mode studies are applied to the shear layer collapse paradigm for the onset of density limit phenomena. Recent experimental results on edge shear layers and density limit phenomenology are summarized and discussed in the context of L -> H transition physics.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Physics, Fluids & Plasmas
Etienne Gravier, Thomas Drouot, Maxime Lesur, Alejandro Guillevic, Guillaume Lo-Cascio, Jerome Moritz, Dominique Escande, Giovanni Manfredi
Summary: In a plasma, the interaction between charged particles leads to collective effects, which dominate the dynamics when the coupling parameter g goes to zero (ideal collisionless plasma), while collisions become significant when g approaches 1. A N-body code was developed and used to study the transition between collisionless and collisional regime by solving the dynamics of N infinite parallel plane sheets for ion and electron populations. The numerical collision rates obtained from the code increase linearly with g for both the two-stream instability and Langmuir waves, showing good agreement with the literature's collision rates.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
A. Guillevic, M. Lesur, X. Garbet, P. Diamond, G. Lo-Cascio, Y. Kosuga, E. Gravier, D. Mandal, A. Ghizzo, T. Reveille
Summary: The velocity-space diffusion of charged particles in a one-dimensional turbulent electric field is investigated using numerical trajectories and compared with quasi-linear theory. The study shows that resonance broadening effects become significant for a Kubo number of a few percent. Diffusion increases as a power law with D / K-3 / E-3/2 for large Kubo numbers. At large Kubo numbers, diffusion occurs at velocities higher than the resonant region, where quasi-linear theory predicts negligible diffusion. The velocity distribution deviates from a Gaussian for times much larger than the trapped particle flight time and the autocorrelation time, but the variance increases linearly in time with a Hurst parameter of H similar to 0.5.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
C. Y. Wang, W. W. Xiao, Y. Ren, P. H. Diamond, X. B. Peng, J. T. Ma, W. J. Zhong
Summary: An intrinsic evolution in the decoupling-coupling-decoupling (DCD) of the electron density and temperature responding to the magnetic field change is observed in a cylindrical laboratory plasma device. Experimental results show that the density and the temperature decouple in the low magnetic field, couple with higher magnetic field, and decouple again with a continuous magnetic field increase. An element physical picture of the DCD regime is unraveled based on the analyses of gradient lengths, the turbulence propagation directions, the turbulence spatial scales, and the relationship between the normalized collision rates and the poloidal mode numbers.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
D. Mandal, M. Lesur, E. Gravier, J. N. Sama, A. Guillevic, Y. Sarazin, X. Garbet
Summary: Trapped ion modes (TIMs) are studied using a global linear analysis and a spectral method. The radial profile of the particle drift velocity is considered in the analysis. The linear growth rates of TIM instability are investigated under different temperature profiles and precession frequencies of trapped ions. The growth rate depends on the logarithmic gradients of temperature, density, and equilibrium Hamiltonian. The results are compared with a semi-Lagrangian based linear Vlasov solver and show good accuracy.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Physics, Fluids & Plasmas
Nami Li, X. Q. Xu, P. H. Diamond, T. Zhang, X. Liu, Y. F. Wang, N. Yan, G. S. Xu
Summary: This paper explores the broadening of the stable scrape-off layer (SOL) by pedestal peeling-ballooning (P-B) magnetohydrodynamic (MHD) turbulence. The study shows that the fluctuation energy density flux increases the heat load width lambda q. The spreading process is found to be influenced by pressure fluctuation correlation length, with P-B turbulence being particularly effective due to its large effective mixing length. The findings have significant implications for future fusion reactor designs.
Article
Physics, Fluids & Plasmas
R. Hong, T. L. Rhodes, P. H. Diamond, Y. Ren, L. Zeng, X. Jian, K. Barada, G. Wang, W. A. Peebles
Summary: We report on the observation of spatially asymmetric turbulent structures in high-collisionality H-mode plasmas on DIII-D tokamak. These structures develop from shorter wavelength turbulence and have a radially elongated structure. The turbulence spans a broad radial range, leading to streamer-like transport events. The emergence of long-radial-range-correlated (LRRC) transport events may explain the degrading nature of H-mode core plasma confinement.
Article
Physics, Fluids & Plasmas
K. Lim, X. Garbet, Y. Sarazin, E. Gravier, M. Lesur, G. Lo-Cascio, T. Rouyer
Summary: The effect of toroidal rotation on tungsten transport in tokamaks is studied using nonlinear simulations with the GYSELA code. Results show that toroidal rotation induces a poloidal asymmetry in tungsten accumulation, enhancing neoclassical inward convection. Core accumulation is mainly driven by inward neoclassical convection, but roto-diffusion becomes significant with continued momentum injection, generating outward turbulent flux.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
R. Hong, T. L. Rhodes, Y. Ren, P. H. Diamond, X. Jian, L. Zeng, K. Barada, Z. Yan, G. R. McKee
Summary: A dimensionless collisionality scan on DIII-D tokamak reveals the development of spatially asymmetric turbulent structures with long-radial-range correlation in the mid-radius region of high collisionality discharges. These structures are likely driven by electron-temperature-gradient mode and show characteristics of self-organized criticality. The magnitude and radial scale of the turbulent structures increase when the flow shearing rate decreases, and they are correlated with degraded energy confinement time.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
J. Moritz, S. Heuraux, N. Lemoine, M. Lesur, E. Gravier, F. Brochard, L. Marot, P. Hiret
Summary: The surface temperature of a tungsten surface facing hot hydrogen plasma is evaluated based on 1d/3v particle-in-cell simulations. The simulations take into account thermionic emission, surface radiation, and heat conduction through the wall. A transition from a cold temperature surface to a hot one occurs for a critical thermal conductivity, and this transition leads to a space charge limited regime. The timing of electron emission can greatly affect the final surface temperature.
PHYSICS OF PLASMAS
(2023)
