Tunable Electronic Structure and Topological Properties of $LnPn$ ($Ln$=Ce, Pr, Gd, Sm, Yb; $Pn$=Sb, Bi)

TL;DR

This study systematically investigates the electronic structures and topological phases of LnPn compounds using first principles calculations, revealing trends in band inversion and topological transitions related to lanthanide contraction.

Contribution

It provides a comprehensive first principles analysis of LnPn compounds, highlighting the impact of lanthanide contraction on their topological properties and identifying specific topological phase transitions.

Findings

Band inversion decreases from Ce to Yb in LnPn compounds.

Topologically nontrivial to trivial transition occurs near SmSb and DyBi.

Hybrid functional and modified Becke-Johnson methods agree with experimental observations.

Abstract

We have performed systematic first principles study of the electronic structure and band topology properties of $LnPn$ compounds ($Ln$=Ce, Pr, Gd, Sm, Yb; $Pn$=Sb, Bi). Assuming the $f$-electrons are well localized in these materials, both hybrid functional and modified Becke-Johnson calculations yield electronic structure in good agreement with experimental observations, while generalized gradient approximation calculations severely overestimate the band inversions. From Ce to Yb, a systematic reduction of band inversion with respect to the increasing $Ln$ atomic number is observed, and $\mathcal{Z}_2$ for Ce$Pn$ and Yb$Pn$ are [1;000] and [0;000], respectively. In both hybrid functional and modified Becke-Johns calculations, a topologically nontrivial to trivial transition is expected around SmSb for the antimonides and around DyBi for the bismuthides. Such variation is related with lanthanide contraction, but is different from simple pressure effect.