scholarly journals Spectral signatures of the surface anomalous Hall effect in magnetic axion insulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mingqiang Gu ◽  
Jiayu Li ◽  
Hongyi Sun ◽  
Yufei Zhao ◽  
Chang Liu ◽  
...  
Keyword(s):  
Hall Effect ◽  
Three Dimensional ◽  
Surface States ◽  
Side Surface ◽  
Anomalous Hall Effect ◽  
Spectral Signatures ◽  
Model Hamiltonian ◽  
Weyl Semimetals ◽  
Significant Step ◽  
Topological Surface

AbstractThe topological surface states of magnetic topological systems, such as Weyl semimetals and axion insulators, are associated with unconventional transport properties such as nonzero or half-quantized surface anomalous Hall effect. Here we study the surface anomalous Hall effect and its spectral signatures in different magnetic topological phases using both model Hamiltonian and first-principles calculations. We demonstrate that by tailoring the magnetization and interlayer electron hopping, a rich three-dimensional topological phase diagram can be established, including three types of topologically distinct insulating phases bridged by Weyl semimetals, and can be directly mapped to realistic materials such as MnBi2Te4/(Bi2Te3)n systems. Among them, we find that the surface anomalous Hall conductivity in the axion-insulator phase is a well-localized quantity either saturated at or oscillating around e2/2h, depending on the magnetic homogeneity. We also discuss the resultant chiral hinge modes embedded inside the side surface bands as the potential experimental signatures for transport measurements. Our study is a significant step forward towards the direct realization of the long-sought axion insulators in realistic material systems.

Giant photoinduced anomalous Hall effect of the topological surface states in three dimensional topological insulators Bi2Te3

2020 ◽  
Vol 116 (14) ◽  
pp. 141603
Author(s):  
Jinling Yu ◽  
Wenyi Wu ◽  
Yumeng Wang ◽  
Kejing Zhu ◽  
Xiaolin Zeng ◽  
...  
Keyword(s):  
Hall Effect ◽  
Topological Insulators ◽  
Three Dimensional ◽  
Surface States ◽  
Anomalous Hall Effect ◽  
Topological Surface

scholarly journals Natural van der Waals heterostructural single crystals with both magnetic and topological properties

2019 ◽  
Vol 5 (11) ◽  
pp. eaax9989 ◽  
Author(s):  
Jiazhen Wu ◽  
Fucai Liu ◽  
Masato Sasase ◽  
Koichiro Ienaga ◽  
Yukiko Obata ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Hall Effect ◽  
Exchange Coupling ◽  
Van Der Waals ◽  
Surface States ◽  
Anomalous Hall Effect ◽  
Topological Quantum ◽  
Magnetic Layers ◽  
Topological Surface ◽  
Ferromagnetic Hysteresis

Heterostructures having both magnetism and topology are promising materials for the realization of exotic topological quantum states while challenging in synthesis and engineering. Here, we report natural magnetic van der Waals heterostructures of (MnBi2Te4)m(Bi2Te3)n that exhibit controllable magnetic properties while maintaining their topological surface states. The interlayer antiferromagnetic exchange coupling is gradually weakened as the separation of magnetic layers increases, and an anomalous Hall effect that is well coupled with magnetization and shows ferromagnetic hysteresis was observed below 5 K. The obtained homogeneous heterostructure with atomically sharp interface and intrinsic magnetic properties will be an ideal platform for studying the quantum anomalous Hall effect, axion insulator states, and the topological magnetoelectric effect.

scholarly journals Anomalous Hall effect in Weyl semimetal half-Heusler compounds RPtBi (R = Gd and Nd)

2018 ◽  
Vol 115 (37) ◽  
pp. 9140-9144 ◽  
Author(s):  
Chandra Shekhar ◽  
Nitesh Kumar ◽  
V. Grinenko ◽  
Sanjay Singh ◽  
R. Sarkar ◽  
...  
Keyword(s):  
Hall Effect ◽  
Muon Spin ◽  
Surface States ◽  
Anomalous Hall Effect ◽  
Chiral Anomaly ◽  
Heusler Compounds ◽  
Weyl Semimetal ◽  
Spin Resonance ◽  
Topological Surface ◽  
Topological Semimetals

Topological materials ranging from topological insulators to Weyl and Dirac semimetals form one of the most exciting current fields in condensed-matter research. Many half-Heusler compounds, RPtBi (R = rare earth), have been theoretically predicted to be topological semimetals. Among various topological attributes envisaged in RPtBi, topological surface states, chiral anomaly, and planar Hall effect have been observed experimentally. Here, we report an unusual intrinsic anomalous Hall effect (AHE) in the antiferromagnetic Heusler Weyl semimetal compounds GdPtBi and NdPtBi that is observed over a wide temperature range. In particular, GdPtBi exhibits an anomalous Hall conductivity of up to 60 Ω−1⋅cm−1 and an anomalous Hall angle as large as 23%. Muon spin-resonance (μSR) studies of GdPtBi indicate a sharp antiferromagnetic transition (TN) at 9 K without any noticeable magnetic correlations above TN. Our studies indicate that Weyl points in these half-Heuslers are induced by a magnetic field via exchange splitting of the electronic bands at or near the Fermi energy, which is the source of the chiral anomaly and the AHE.

scholarly journals Giant room temperature anomalous Hall effect and tunable topology in a ferromagnetic topological semimetal Co2MnAl

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Peigang Li ◽  
Jahyun Koo ◽  
Wei Ning ◽  
Jinguo Li ◽  
Leixin Miao ◽  
...  
Keyword(s):  
Hall Effect ◽  
Room Temperature ◽  
Transport Phenomena ◽  
Surface States ◽  
Anomalous Hall Effect ◽  
Spintronic Devices ◽  
Structure Topology ◽  
Weyl Semimetal ◽  
Weyl Semimetals ◽  
Record Value

Abstract Weyl semimetals exhibit unusual surface states and anomalous transport phenomena. It is hard to manipulate the band structure topology of specific Weyl materials. Topological transport phenomena usually appear at very low temperatures, which sets challenges for applications. In this work, we demonstrate the band topology modification via a weak magnetic field in a ferromagnetic Weyl semimetal candidate, Co2MnAl, at room temperature. We observe a tunable, giant anomalous Hall effect (AHE) induced by the transition involving Weyl points and nodal rings. The AHE conductivity is as large as that of a 3D quantum AHE, with the Hall angle (ΘH) reaching a record value ($$\tan {\Theta }^{H}=0.21$$ tan Θ H = 0.21 ) at the room temperature among magnetic conductors. Furthermore, we propose a material recipe to generate large AHE by gaping nodal rings without requiring Weyl points. Our work reveals an intrinsically magnetic platform to explore the interplay between magnetic dynamics and topological physics for developing spintronic devices.

Three-dimensional quantum Hall effect in Weyl and double-Weyl semimetals

2018 ◽  
Vol 382 (44) ◽  
pp. 3205-3210
Author(s):  
Zhi-Peng Gao ◽  
Zhi Li ◽  
Dan-Wei Zhang
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Three Dimensional ◽  
Weyl Semimetals

scholarly journals Progress Review on Topological Properties of Heusler Materials

2020 ◽  
Vol 213 ◽  
pp. 02016
Author(s):  
Zhi Lin
Keyword(s):  
Hall Effect ◽  
Surface States ◽  
Anomalous Hall Effect ◽  
Edge State ◽  
Chiral Anomaly ◽  
Dirac Fermion ◽  
High Symmetry ◽  
Heusler Compounds ◽  
Topological Properties ◽  
Topological State

Starting from crystal, electronic and magnetic structures of Heusler compounds, this paper studies the new topological materials related to Heusler compounds and their topological properties, such as anomalous Hall effect, skyrmions, chiral anomaly, Dirac fermion, Weyl fermion, transverse Nernst thermoelectric effect, thermal spintronics and topological surface states. It can be discovered that the topological state of Heusler compound can be well protected due to its high symmetry, thus producing rich topological properties. Heusler materials belonged to Weyl semimetals usually have strong anomalous Hall effect, and the Heusler materials with doping or Anomalous Nernst Effect (ANE) usually have higher thermoelectric figure of merit. These anomalous effects are closely related to the strong spin–orbit interaction. In application, people can use the non-dissipative edge state of quantum anomalous Hall effect to develop a new generation of low-energy transistors and electronic devices. The conversion efficiency of thermoelectric materials can be improved by ANE, and topological superconductivity can be used to promote the progress of quantum computation.

scholarly journals Quantum Hall Effect from the Topological Surface States of Strained Bulk HgTe

2011 ◽  
Vol 106 (12) ◽  
Author(s):  
C. Brüne ◽  
C. X. Liu ◽  
E. G. Novik ◽  
E. M. Hankiewicz ◽  
H. Buhmann ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Surface States ◽  
Topological Surface

scholarly journals Nonlinear dynamics induced anomalous Hall effect in topological insulators

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 001543-001553
Author(s):  
Guanglei Wang ◽  
Hongya Xu ◽  
Ying-Cheng Lai
Keyword(s):  
Hall Effect ◽  
Three Dimensional ◽  
Anomalous Hall Effect ◽  
Transmission Probability ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Alternative Mechanism ◽  
Final States ◽  
Nonlinear Dynamical ◽  
Dynamical Behaviors

We uncover an alternative mechanism for anomalous Hall effect. In particular, we investigate the magnetisation dynamics of an insulating ferromagnet (FM) deposited on the surface of a three-dimensional topological insulator (TI), subject to an external voltage. The spin-polarised current on the TI surface induces a spin-transfer torque on the magnetisation of the top FM while its dynamics can change the transmission probability of the surface electrons through the exchange coupling and hence the current. We find a host of nonlinear dynamical behaviors including multistability, chaos, and phase synchronisation. Strikingly, a dynamics mediated Hall-like current can arise, which exhibits a nontrivial dependence on the channel conductance. We develop a physical understanding of the mechanism that leads to the anomalous Hall effect. The nonlinear dynamical origin of the effect stipulates that a rich variety of final states exist, implying that the associated Hall current can be controlled to yield desirable behaviors. The phenomenon can find applications in Dirac-material based spintronics.

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