Density of States and Magnetic Correlations at a Metal-Mott Insulator Interface

TL;DR

This study investigates the interplay of metallic and Mott insulator phases at a 2D interface using quantum Monte Carlo, revealing induced metallicity, persistent magnetic correlations, and boundary singlet formation.

Contribution

It provides a detailed quantum Monte Carlo analysis of the density of states and magnetic correlations at a metal-Mott insulator interface, highlighting new interfacial phenomena.

Findings

Induced metallic behavior extends several lattice spacings into the insulator.

Antiferromagnetic correlations are weak on the metallic side.

Boundary singlets form at high interface hopping, shielding the systems.

Abstract

The possibility of novel behavior at interfaces between strongly and weakly correlated materials has come under increased study recently. In this paper, we use determinant Quantum Monte Carlo to determine the inter-penetration of metallic and Mott insulator physics across an interface in the two dimensional Hubbard Hamiltonian. We quantify the behavior of the density of states at the Fermi level and the short and long range antiferromagnetism as functions of the distance from the interface and with different interaction strength, temperature and hopping across the interface. Induced metallic behavior into the insulator is evident over several lattice spacings, whereas antiferromagnetic correlations remain small on the metallic side. At large interface hopping, singlets form between the two boundary layers, shielding the two systems from each other.