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Institute for Condensed Matter Theory Seminar: "Quantized Thermoelectric Hall Effect and Zero-Field Nonlinear Hall Effect"

Event Type
The Physics Department
190 ESB
Apr 24, 2019   11:00 am  
Liang Fu, Massachusetts Institute of Technology
Originating Calendar
Physics - Institute for Condensed Matter Theory Seminar

I will describe two new Hall effects. First, I will show thermoelectric Hall conductivity, which relates transverse charge current to temperature gradient, is quantized in three-dimensional Dirac/Weyl materials in the quantum limit. The quantized value is independent of magnetic field, carrier density, or disorder. This quantization results from chiral Landau levels of Dirac/Weyl electrons and enables an unprecedented growth in the thermopower and the thermoelectric figure of merit. Second, I will demonstrate a novel nonlinear Hall effect in nonmagnetic materials at zero magnetic field, where the transverse current increases quadratically with applied electric field. This effect arises from Berry curvature in time-reversal-invariant inversion-breaking systems, which gives rise to anomalous velocity in a current-carrying state. Experimental observations and potential applications of thermoelectric Hall effect and nonlinear Hall effect will be discussed.

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