Quasi-2D anomalous Hall Mott insulator of topologically engineered Jeff =1/2 electrons

TL;DR

This paper explores a model system combining complex hopping and electronic correlation, revealing an anomalous Hall effect and large magnetic anisotropy due to the interplay of topology and correlations in a Mott insulator.

Contribution

It introduces a novel pseudospin-half Hubbard model on a square lattice that demonstrates the coexistence of topological effects and strong correlations, leading to unique magnetic and transport phenomena.

Findings

Observation of anomalous Hall effect with non-monotonic temperature dependence

Identification of giant magnon gap indicating large Ising anisotropy

Evidence of interplay between electronic topology and correlation in Mott insulators

Abstract

We investigate an experimental toy-model system of a pseudospin-half square-lattice Hubbard Hamiltonian in [(SrIrO3)1/(CaTiO3)1] to include both nontrivial complex hopping and moderate electronic correlation. While the former induces electronic Berry phases as anticipated from the weak-coupling limit, the later stabilizes an antiferromagnetic (AFM) Mott insulator ground state in analogous to the strong-coupling limit. Their combined results in the real system are found to be an anomalous Hall effect with a non-monotonic temperature dependence due to the self-competition of the electron-hole pairing in the Mott state, and an exceptionally large Ising anisotropy that is captured as a giant magnon gap beyond the superexchange approach. The unusual phenomena highlight the rich interplay of electronic topology and electronic correlation in the intermediate-coupling regime that is largely unexplored and challenging in theoretical modelling.