Recently, the rare-earth monopnictide compounds LnPn have attracted considerable attention in condensed matter physics studies due to their possible topological properties. We have performed systematic first principles study of the electronic structure and band topology properties of LnPn (Ln=Ce, Pr, Sm, Gd, 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 Z 2 for CePn and YbPn are [1;000] and [0;000], respectively. In both hybrid functional and modified Becke-Johns calculations, a topologically non-trivial 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 effects.
Superconductivity in crystals without inversion symmetry has received extensive attention due to its unconventional pairing and possible nontrivial topological properties. Using first-principles calculations, we systemically study the electronic structure of noncentrosymmetric superconductors A 2 Cr 3 As 3 (A=Na, K, Rb and Cs). Topologically protected triply degenerate points connected by one-dimensional arcs appear along the C 3 axis, coexisting with strong ferromagnetic (FM) fluctuations in the non-superconducting state. Within random phase approximation, our calculations show that strong enhancements of spin fluctuations are present in K 2 Cr 3 As 3 and Rb 2 Cr 3 As 3 , and are substantially reduced in Na 2 Cr 3 As 3 and Cs 2 Cr 3 As 3 . Symmetry analysis of spin-orbit coupling g k suggests that the arc surface states might remain stable in the superconducting state, giving rise to possible nontrivial topological properties. *
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.