Orbital Mott transition in two dimensional Pyrochlore lattice

TL;DR

This paper investigates the orbital Mott transition in a two-dimensional pyrochlore lattice using a two-orbital Hubbard model, revealing phase diagrams, orbital ordering, and unique spectral features at finite temperatures.

Contribution

It introduces a real space Monte Carlo approach to study the finite-temperature phase diagram of the model, highlighting the role of inter-orbital hopping and ferro-orbital ordering.

Findings

Identification of temperature-interaction phase diagrams showing Mott transition and orbital order.

Discovery of ferro-orbital ordering driven by inter-orbital hopping.

Observation of a two-peak feature in optical conductivity due to lattice geometry.

Abstract

We study orbital Mott transition in two dimensional pyrochlore lattice, using a two orbital Hubbard model with only inter-orbital electronic hopping. We use a real space Monte Carlo based approach to study the model at finite temperature, and establish temperature-interaction phase diagrams that highlight the Mott transition, orbital ordering, and spectral trends, and possible window of pseudo gap. Due to only inter-orbital hopping, the Mott insulator `generates' ferro exchange resulting in ferro-orbital ordering, with T$_{corr}/t$ peaked at $\approx$ 0.2 around $U/t \approx 6$. The optical conductivity shows unusual two peak feature due to two dimensional pyrochlore lattice.