Quantum Nonlinear Hall Effect Induced by Berry Curvature Dipole in Time-Reversal Invariant Materials

AbstractIn a system with broken inversion symmetry, a second-order nonlinear Hall effect can survive even in the presence of time-reversal symmetry. In this work, we show that a giant nonlinear Hall effect can exist in twisted bilayer WTe2 system. The Berry curvature dipole of twisted bilayer WTe2 (θ = 29.4°) can reach up to ~1400 Å, which is much larger than that in previously reported nonlinear Hall systems. In twisted bilayer WTe2 system, there exist abundant band anticrossings and band inversions around the Fermi level, which brings a complicated distribution of Berry curvature, and leads to the nonlinear Hall signals that exhibit dramatically oscillating behavior in this system. Its large amplitude and high tunability indicate that the twisted bilayer WTe2 can be an excellent platform for studying the nonlinear Hall effect.

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Topological thermal Hall effect due to Weyl magnons

Canadian Journal of Physics ◽

10.1139/cjp-2018-0059 ◽

2018 ◽

Vol 96 (11) ◽

pp. 1216-1223 ◽

Cited By ~ 4

Author(s):

S.A. Owerre

Keyword(s):

Hall Effect ◽

Time Reversal ◽

Low Temperatures ◽

Three Dimensional ◽

Zero Magnetic Field ◽

Time Reversal Symmetry ◽

Frustrated Magnets ◽

Berry Curvature ◽

Theoretical Evidence ◽

Distribution Distance

We present the first theoretical evidence of zero magnetic field topological (anomalous) thermal Hall effect due to Weyl magnons in stacked noncoplanar frustrated kagomé antiferromagnets. The Weyl magnons in this system result from macroscopically broken time-reversal symmetry by the scalar spin chirality of noncoplanar chiral spin textures. Most importantly, they come from the lowest excitation, therefore they can be easily observed experimentally at low temperatures due to the population effect. Similar to electronic Weyl nodes close to the Fermi energy, Weyl magnon nodes at the lowest excitation are the most important. Indeed, we show that the topological (anomalous) thermal Hall effect in this system arises from nonvanishing Berry curvature due to Weyl magnon nodes at the lowest excitation, and it depends on their distribution (distance) in momentum space. The present result paves the way to directly probe low excitation Weyl magnons and macroscopically broken time-reversal symmetry in three-dimensional frustrated magnets with the anomalous thermal Hall effect.

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Ferroelectric nonlinear anomalous Hall effect in few-layer WTe2

npj Computational Materials ◽

10.1038/s41524-019-0257-1 ◽

2019 ◽

Vol 5 (1) ◽

Cited By ~ 6

Author(s):

Hua Wang ◽

Xiaofeng Qian

Keyword(s):

Magnetic Field ◽

Hall Effect ◽

Time Reversal ◽

First Principles ◽

Hall Current ◽

Anomalous Hall Effect ◽

New Order ◽

Berry Curvature ◽

Weyl Semimetals ◽

Nonlinear Quantum

AbstractUnder broken time reversal symmetry such as in the presence of external magnetic field or internal magnetization, a transverse voltage can be established in materials perpendicular to both longitudinal current and applied magnetic field, known as classical Hall effect. However, this symmetry constraint can be relaxed in the nonlinear regime, thereby enabling nonlinear anomalous Hall current in time-reversal invariant materials – an underexplored realm with exciting new opportunities beyond classical linear Hall effect. Here, using group theory and first-principles theory, we demonstrate a remarkable ferroelectric nonlinear anomalous Hall effect in time-reversal invariant few-layer WTe2 where nonlinear anomalous Hall current switches in odd-layer WTe2 except 1T′ monolayer while remaining invariant in even-layer WTe2 upon ferroelectric transition. This even-odd oscillation of ferroelectric nonlinear anomalous Hall effect was found to originate from the absence and presence of Berry curvature dipole reversal and shift dipole reversal due to distinct ferroelectric transformation in even and odd-layer WTe2. Our work not only treats Berry curvature dipole and shift dipole on an equal footing to account for intraband and interband contributions to nonlinear anomalous Hall effect, but also establishes Berry curvature dipole and shift dipole as new order parameters for noncentrosymmetric materials. The present findings suggest that ferroelectric metals and Weyl semimetals may offer unprecedented opportunities for the development of nonlinear quantum electronics.

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Giant c-axis nonlinear anomalous Hall effect in Td-MoTe2 and WTe2

Nature Communications ◽

10.1038/s41467-021-22343-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Archana Tiwari ◽

Fangchu Chen ◽

Shazhou Zhong ◽

Elizabeth Drueke ◽

Jahyun Koo ◽

...

Keyword(s):

Hall Effect ◽

Time Reversal ◽

Low Temperatures ◽

Magnetic Order ◽

Anomalous Hall Effect ◽

Time Reversal Symmetry ◽

Inversion Center ◽

Scattering Process ◽

Berry Curvature ◽

Skew Scattering

AbstractWhile the anomalous Hall effect can manifest even without an external magnetic field, time reversal symmetry is nonetheless still broken by the internal magnetization of the sample. Recently, it has been shown that certain materials without an inversion center allow for a nonlinear type of anomalous Hall effect whilst retaining time reversal symmetry. The effect may arise from either Berry curvature or through various asymmetric scattering mechanisms. Here, we report the observation of an extremely large c-axis nonlinear anomalous Hall effect in the non-centrosymmetric Td phase of MoTe2 and WTe2 without intrinsic magnetic order. We find that the effect is dominated by skew-scattering at higher temperatures combined with another scattering process active at low temperatures. Application of higher bias yields an extremely large Hall ratio of E⊥/E|| = 2.47 and corresponding anomalous Hall conductivity of order 8 × 107 S/m.

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Interface-induced sign reversal of the anomalous Hall effect in magnetic topological insulator heterostructures

Nature Communications ◽

10.1038/s41467-020-20349-z ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Fei Wang ◽

Xuepeng Wang ◽

Yi-Fan Zhao ◽

Di Xiao ◽

Ling-Jie Zhou ◽

...

Keyword(s):

Hall Effect ◽

Electric Fields ◽

First Principles ◽

Berry Phase ◽

Condensed Matter ◽

Anomalous Hall Effect ◽

First Principles Calculations ◽

Sign Reversal ◽

Berry Curvature ◽

Topological Materials

AbstractThe Berry phase picture provides important insights into the electronic properties of condensed matter systems. The intrinsic anomalous Hall (AH) effect can be understood as the consequence of non-zero Berry curvature in momentum space. Here, we fabricate TI/magnetic TI heterostructures and find that the sign of the AH effect in the magnetic TI layer can be changed from being positive to negative with increasing the thickness of the top TI layer. Our first-principles calculations show that the built-in electric fields at the TI/magnetic TI interface influence the band structure of the magnetic TI layer, and thus lead to a reconstruction of the Berry curvature in the heterostructure samples. Based on the interface-induced AH effect with a negative sign in TI/V-doped TI bilayer structures, we create an artificial “topological Hall effect”-like feature in the Hall trace of the V-doped TI/TI/Cr-doped TI sandwich heterostructures. Our study provides a new route to create the Berry curvature change in magnetic topological materials that may lead to potential technological applications.

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2D‐Berry‐Curvature‐Driven Large Anomalous Hall Effect in Layered Topological Nodal‐Line MnAlGe

Advanced Materials ◽

10.1002/adma.202006301 ◽

2021 ◽

pp. 2006301

Author(s):

Satya N. Guin ◽

Qiunan Xu ◽

Nitesh Kumar ◽

Hsiang‐Hsi Kung ◽

Sydney Dufresne ◽

...

Keyword(s):

Hall Effect ◽

Anomalous Hall Effect ◽

Nodal Line ◽

Berry Curvature ◽

Curvature Driven

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Nonlinear Hall Effect with Time‐Reversal Symmetry: Theory and Material Realizations

Advanced Quantum Technologies ◽

10.1002/qute.202100056 ◽

2021 ◽

pp. 2100056

Author(s):

Carmine Ortix

Keyword(s):

Hall Effect ◽

Time Reversal ◽

Time Reversal Symmetry ◽

Symmetry Theory

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Chiral Anomaly, Topological Field Theory, and Novel States of Matter

Reviews in Mathematical Physics ◽

10.1142/s0129055x1840007x ◽

2018 ◽

Vol 30 (06) ◽

pp. 1840007 ◽

Cited By ~ 2

Author(s):

Jürg Fröhlich

Keyword(s):

Hall Effect ◽

Quantum Hall Effect ◽

Time Reversal ◽

Topological Insulators ◽

Large Scale ◽

Quantum Hall ◽

Chiral Anomaly ◽

Open Problems ◽

Spin Currents ◽

Spin Orbit Interactions

Starting with a description of the motivation underlying the analysis presented in this paper and a brief survey of the chiral anomaly, I proceed to review some basic elements of the theory of the quantum Hall effect in 2D incompressible electron gases in an external magnetic field, (“Hall insulators”). I discuss the origin and role of anomalous chiral edge currents and of anomaly inflow in 2D insulators with explicitly or spontaneously broken time reversal, i.e. in Hall insulators and “Chern insulators”. The topological Chern–Simons action yielding the large-scale response equations for the 2D bulk of such states of matter is displayed. A classification of Hall insulators featuring quasi-particles with abelian braid statistics is sketched. Subsequently, the chiral edge spin currents encountered in some time-reversal invariant 2D topological insulators with spin-orbit interactions and the bulk response equations of such materials are described. A short digression into the theory of 3D topological insulators, including “axionic insulators”, follows next. To conclude, some open problems are described and a problem in cosmology related to axionic insulators is mentioned. As far as the quantum Hall effect and the spin currents in time-reversal invariant 2D topological insulators are concerned, this review is based on extensive work my collaborators and I carried out in the early 1990’s. Dedicated to the memory of Ludvig Dmitrievich Faddeev — a great scientist who will be remembered

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