Thermal and electrical quantum Hall effects in ferromagnet-topological insulator-ferromagnet junction

TL;DR

This paper provides a theoretical framework for understanding how magnetization direction in ferromagnet-topological insulator-ferromagnet junctions influences quantum Hall effects, enabling control over Hall voltages and temperature gradients.

Contribution

It introduces a theoretical model predicting tunable quantum Hall coefficients in FM-TI-FM junctions based on magnetization orientation and system parameters.

Findings

Hall voltage and temperature gradient can be switched from maximal to zero by changing magnetization direction.

Thermal and electrical Hall resistances depend on magnetization, spin-scattering time, and device geometry.

Quantized Hall effects can be suppressed or enhanced through magnetic configuration control.

Abstract

We present the theoretical description for a class of experimental setups that measure quantum Hall coefficients in ferromagnet-topological insulator-ferromagnet (FM-TI-FM) junctions. We predict that varying the magnetization direction in ferromagnets, one can change the induced Hall voltage and transverse temperature gradient from the maximal values, corresponding to the quantized Hall coefficients, down to their complete suppression to zero. We provide detailed analysis of thermal and electrical Hall resistances as functions of the magnetization directions in ferromagnets, the spin-scattering time in TI, and geometrical positions of FM leads and measurement contacts.