Anomalous ground state properties of SmB6 -- a density functional theoretical study

TL;DR

This study uses density functional theory to investigate the electronic structure of SmB6, revealing its metallic ground state and highlighting the importance of spin-orbit coupling, electron correlation, and B 2p - Sm 4f hybridization in its properties.

Contribution

It provides a comprehensive DFT analysis showing metallicity and the role of hybridization in SmB6, aligning with experimental observations.

Findings

SmB6 has a metallic ground state consistent with low temperature anomalies.

Fermi surfaces show Sm 4f electron and hole pockets matching quantum oscillation data.

Significant B 2p contribution suggests hybridization influences exotic physics.

Abstract

We studied the electronic structure of SmB6 employing density functional theory (DFT) using different exchange potentials, spin-orbit coupling (SOC) and electron correlation (U = correlation strength). All the calculations carried out in this study converge to metallic ground state indicating bulk metallicity in SmB6, which is in line with the low temperature anomalies observed in this system. We show that while spin-orbit coupling and electron correlation is important to capture the ground state properties, generalized gradient approximation provides the best description of the Sm 4f multiplets observed in angle-resolved photoemission spectroscopy (ARPES) data. The Fermi surface plots exhibit electron and hole pockets having dominant Sm 4f character; the observation of these Fermi surfaces is consistent with the recent quantum oscillation measurements. In addition to primarily Sm 4f contributions observed at the Fermi level, we discover significantly large contribution from B 2p states compared to weak Sm 5d contributions. This suggests important role of B 2p - Sm 4f hybridization in the exotic physics of this system.