scholarly journals Time-reversal odd transport in bilayer graphene: Hall conductivity and Hall viscosity

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Wei-Han Hsiao
Keyword(s):  
Time Reversal ◽  
Bilayer Graphene ◽  
Hall Conductivity ◽  
Hall Viscosity

scholarly journals DMRG study of strongly interacting $\mathbb{Z}_2$ flatbands: a toy model inspired by twisted bilayer graphene

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Paul Eugenio ◽  
Ceren Dag
Keyword(s):  
Magnetic Field ◽  
Time Reversal ◽  
Ground States ◽  
Bilayer Graphene ◽  
Chern Number ◽  
Strong Interactions ◽  
Time Reversal Symmetry ◽  
Density Matrix Renormalization ◽  
Topological Quantum ◽  
Twisted Bilayer Graphene

Strong interactions between electrons occupying bands of opposite (or like) topological quantum numbers (Chern=\pm1=±1), and with flat dispersion, are studied by using lowest Landau level (LLL) wavefunctions. More precisely, we determine the ground states for two scenarios at half-filling: (i) LLL’s with opposite sign of magnetic field, and therefore opposite Chern number; and (ii) LLL’s with the same magnetic field. In the first scenario – which we argue to be a toy model inspired by the chirally symmetric continuum model for twisted bilayer graphene – the opposite Chern LLL’s are Kramer pairs, and thus there exists time-reversal symmetry (\mathbb{Z}_2ℤ2). Turning on repulsive interactions drives the system to spontaneously break time-reversal symmetry – a quantum anomalous Hall state described by one particle per LLL orbital, either all positive Chern |{++\cdots+}\rangle|++⋯+⟩ or all negative |{--\cdots-}\rangle|−−⋯−⟩. If instead, interactions are taken between electrons of like-Chern number, the ground state is an SU(2)SU(2) ferromagnet, with total spin pointing along an arbitrary direction, as with the \nu=1ν=1 spin-\frac{1}{2}12 quantum Hall ferromagnet. The ground states and some of their excitations for both of these scenarios are argued analytically, and further complimented by density matrix renormalization group (DMRG) and exact diagonalization.

scholarly journals Hall viscosity, topological states and effective theories

2014 ◽  
Vol 28 (15) ◽  
pp. 1430007 ◽  
Author(s):  
Carlos Hoyos
Keyword(s):  
Transport Coefficient ◽  
Hall Conductivity ◽  
Topological Phases ◽  
Topological Order ◽  
Topological States ◽  
Effective Theories ◽  
Hall Viscosity ◽  
Galilean Invariant

Hall viscosity is a dissipationless transport coefficient whose value is quantized in units of the density in some topological phases and may be used as a measure of topological order. I give an overview of the Hall viscosity, its relation to Hall conductivity in Galilean invariant theories and its realization in effective theories.

scholarly journals Observation of Time-Reversal Invariant Helical Edge-Modes in Bilayer Graphene/WSe2 Heterostructure

ACS Nano ◽  
2020 ◽  
Author(s):  
Priya Tiwari ◽  
Saurabh Kumar Srivastav ◽  
Sujay Ray ◽  
Tanmoy Das ◽  
Aveek Bid
Keyword(s):  
Time Reversal ◽  
Bilayer Graphene

scholarly journals Hall effects in artificially corrugated bilayer graphene without breaking time-reversal symmetry

2021 ◽  
Vol 4 (2) ◽  
pp. 116-125
Author(s):  
Sheng-Chin Ho ◽  
Ching-Hao Chang ◽  
Yu-Chiang Hsieh ◽  
Shun-Tsung Lo ◽  
Botsz Huang ◽  
...  
Keyword(s):  
Time Reversal ◽  
Bilayer Graphene ◽  
Time Reversal Symmetry ◽  
Hall Effects ◽  
Breaking Time
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