Orbital correlations in ultrathin films of late transition metals

TL;DR

This paper presents a two-orbital Hubbard model for ultrathin transition metal films, revealing how electron correlations lead to orbital liquid states that influence magnetic properties.

Contribution

It introduces a novel model capturing orbital correlations and frustration effects in ultrathin transition metal films, highlighting the orbital liquid state.

Findings

Mott-Hund's interaction induces ferromagnetic orbital correlations

Orbital frustration prevents orbital ordering, leading to an orbital liquid state

Orbital liquid state affects phenomena involving spin-orbit coupling, like magnetic anisotropy

Abstract

We develop a two-orbital Hubbard model of electron correlations in ultrathin (111)-oriented fcc films of late transition metals such as Co and Ni. Our model indicates that the Mott-Hund's interaction results in ferromagnetic nearest-neighbor orbital correlations. Frustration associated with the mismatch between orbital and crystal symmetries prevents orbital ordering, resulting in the orbital liquid state. This state can be manifested in phenomena involving spin-orbit coupling, such as magnetic anisotropy.