Tunable electronic structure and topological properties of LnPn (Ln=Ce, Pr, Sm, Gd, Yb; Pn=Sb, Bi)

Abstract

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.

Magnetotransport and electronic structure of the antiferromagnetic semimetal YbAs

“…Meanwhile in SmSb, the analysis of the Shubnikov-de Haas (SdH) oscillations indicates a topologically non-trivial band structure [29]. Topological electronic structures were detected using angle-resolved photoemission spectroscopy (ARPES) for several rareearth mono-bismuthides (Ce, Pr, Sm, Gd)Bi, showing tunable bulk band inversions and corresponding surface states [30], where the ARPES results agree well with density functional theory (DFT) calculations assuming the 4f -electrons to be well localized [32].…”

“…Searching for correlated and magnetic materials with topologically non-trivial electronic structures has recently led to the discovery of novel topological phases, such as topological Kondo insulators [1,2], magnetic topological insulators [3][4][5][6], magnetic Weyl semimetals [7][8][9][10] and Weyl-Kondo semimetals [11,12]. The LnX series crystallizing in the cubic NaCl-type structure [13](Ln = rare-earth and X = As, Sb or Bi) is a large family of semimetals where topologically nontrivial band structures have been found to exist with electronic correlations and magnetism [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. For example, evidence was found that CeSb hosts Weyl fermions in the fieldinduced ferromagnetic state [14], while NdSb was reported to be a Dirac semimetal with antiferromagnetic (AFM) order [25][26][27].…”

Anomalous quantum oscillations and evidence for a non-trivial Berry phase in SmSb

“…Furthermore, the amplitude of the α-band oscillations is maximum at around 0.8 K, and upon further decreasing the temperature, the amplitude decreases. Meanwhile, the angular dependence of F α can be fitted with the equation for anisotropic three-dimensional ellipsoidal pockets [51](see Supplementary Figure 2), which can describe the anisotropic bullet-like Fermi surface pockets around the X-points, corresponding to the bulk Fermi surface of the α-band [23,29]. However, although the SdH and dHvA data coincide well at higher temperatures, below around 2.5 K there is a significant deviation which cannot be accounted for by the LK formula.…”

Witnessing quantum criticality and entanglement in the triangular antiferromagnet KYbSe$_2$

“…Localized f-electron magnetism in Mott-Hubbard systems has traditionally been a challenge for ab initio Density Func- tional Theory [75,76] (DFT) owing to systematic selfinteraction and static-correlation errors [77] in semi-local approximate exchange correlation (XC) functionals. When fshell magnetism is not important, DFT simulations of rareearth compounds often relegate the f-electrons to a coreshell [78] within a pseudopotential approximation. Such a description yields satisfactory structural property predictions especially in the Lathanides where the f-shell-ligand hybridization is weak [78].…”

“…When fshell magnetism is not important, DFT simulations of rareearth compounds often relegate the f-electrons to a coreshell [78] within a pseudopotential approximation. Such a description yields satisfactory structural property predictions especially in the Lathanides where the f-shell-ligand hybridization is weak [78]. In KYbSe 2 , magnetism is of primary relevance and so f-electrons need to be treated explicitly as valence electrons.…”