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

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.