Quantum-Many-Body Intermetallics: Phase Stability of Fe$_3$Al and Small-Gap Formation in Fe$_2$VAl

TL;DR

This study uses advanced many-body computational methods to analyze phase stability and electronic properties of Fe-Al intermetallics, revealing improved descriptions of charge density, magnetic energy, and a low-temperature charge gap in Fe2VAl.

Contribution

It combines density functional theory with dynamical mean-field theory to better understand electronic correlations and phase stability in Fe-Al intermetallic compounds.

Findings

Enhanced understanding of phase stability of Fe3Al

Observation of a charge-gap in Fe2VAl at low temperatures

The gap structure differs from conventional band theory, indicating strong correlations.

Abstract

Various intermetallic compounds harbor subtle electronic correlation effects. To elucidate this fact for the Fe-Al system, we perform a realistic many-body investigation based on the combination of density functional theory with dynamical mean-field theory in a charge self-consistent manner. A better characterization and understanding of the phase stability of bcc-based D0$_3$-Fe$_3$Al through an improved description of the correlated charge density and the magnetic-energy is achevied. Upon replacement of one Fe sublattice by V, the Heusler compound Fe$_2$VAl is realized, known to display bad-metal behavior and increased specific heat. We here document a charge-gap opening at low temperatures in line with previous experimental work. The gap structure does not match conventional band theory and is reminiscent of (pseudo)gap charateristics in correlated oxides.