Anomalous Hall effects in magnetic weak topological insulator films

TL;DR

This paper systematically explores how magnetism influences weak topological insulator films, revealing various Hall effects without external magnetic fields, and providing new insights into magnetic phenomena in these materials.

Contribution

It is the first comprehensive study of magnetic effects on weak topological insulators, uncovering multiple Hall effects and their underlying mechanisms.

Findings

Discovery of metallic quantum anomalous Hall effect without chiral edge states

Identification of quantized layer and valley-like Hall effects

Observation of higher Hall conductance plateaus in weak topological insulators

Abstract

The interplay between magnetism and strong topological insulator gives rise to distinct new topological phases and various intriguing phenomena, attracting significant attention in recent years. However, magnetic effects in weak topological insulators remain largely unexplored. In this work, we systematically investigate the magnetic effect on thin films of weak topological insulators. We focus on ferromagnetic and antiferromagnetic effects, which have been extensively studied in strong topological insulators, as well as the recently highlighted altermagnetic effect. We reveal that the interplay between magnetism and weak topological insulators leads to a variety of Hall effects in the absence of an external magnetic field, including the metallic quantum anomalous Hall effect without chiral edge states, the quantum anomalous Hall effect with a higher Hall conductance plateau, the quantized layer Hall effect, the metallic half-quantized valley-like Hall effect, and a quantized valley-like Hall effect. This work provides valuable insights for exploring magnetic effect on weak topological insulators.