Mott Transition and Glassiness in the Face Centered Cubic Lattice

TL;DR

This paper investigates the phase transitions and glassy behavior in the half-filled Hubbard model on the face centered cubic lattice, revealing a complex interplay of metallic, insulating, magnetic, and spin glass states driven by interaction strength.

Contribution

It introduces a real space auxiliary field technique to study the Hubbard model on FCC lattice, uncovering novel spin glass and pseudogap phenomena in three-dimensional frustrated systems.

Findings

Identification of paramagnetic metal, antiferromagnetic insulator, and spin glass phases.

Discovery of a narrow interaction window with spin glass behavior.

Observation of crossover from metallic to insulating behavior with increasing interaction.

Abstract

We study the half-filled Hubbard model on the geometrically frustrated face centered cubic (FCC) lattice, using an auxiliary field based real space technique. The low temperature state is a paramagnetic metal at weak interaction, an antiferromagnetic insulator (AFI) with flux like order at intermediate interaction, and an AFI with `C type' order at very strong interaction. Remarkably, there is a narrow window between the paramagnetic metal and the AFI where the system exhibits spin glass behaviour arising from the presence of disordered but `frozen' local moments. The spin glass state is metallic at weaker interaction but shows crossover to pseudogap behaviour and an insulating resistivity with growing interaction. We compare our results to available experiments on FCC and pyrochlore based materials and suggest that several of these features are typical of three dimensional correlated systems with geometric frustration.