Tunable Weyl and Dirac states in the nonsymmorphic compound CeSbTe

Abstract

By establishing magnetic order in a square lattice compound, we introduce the first magnetic “new fermion.”

Charge Density Waves and Magnetism in Topological Semimetal Candidates GdSbxTe2−x−δ

“…Since vacancies are found to exist in orthorhombic GdSb x Te 2− x−δ , particularly when x ≤ 0.21 (Figure S1, Supporting Information), these may also play an important role in the supercell formation. We further note that tetragonal GdSb 0.85 Te 1.15 does have the same c ‐axis as the subcell, just as that in CeSbTe, but unlike in tetragonal LaSbTe, where it is doubled.…”

“…In previous studies, single crystals of rare earth ditellurides ( Ln Te 2 ) were synthesized by several different methods, including chemical vapor transport (CVT), self‐flux method, molten alkali–metal–halide flux method, mineralization from a nominally stoichiometry binary mixture of elements, and high‐temperature Bridgman method . For synthesis of the ternary compound with Sb, we adopted CVT using iodine as the transport agent, similar to the single crystal growth of CeSbTe reported in recent work . By varying the amount of Sb in the starting materials, the Sb composition in GdSb x Te 2− x − δ is controlled.…”

“…The class of square‐net materials, which includes the well‐known topological nodal‐line semimetal ZrSiS, as well as the highly anisotropic Dirac semimetal SrMnBi 2 , is known to host many TSMs. For example, CeSbTe, which is isostructural and isoelectronic to nodal‐line semimetal ZriSiS (space group P 4/ nmm ), stands out as one of few magnetic TSMs that provide an opportunity to study tunable Weyl and Dirac states in a single material system. Replacing Ce by other rare‐earth elements might affect the magnetic properties, which is part of the motivation for the study of the analogue GdSbTe.…”

The Role of Delocalized Chemical Bonding in Square-Net-Based Topological Semimetals

“…The compounds in the yellow region are mostly established TSMs, for example ZrSiS and related compounds with M=Zr or Hf, X=Si, Ge, or Sn, and Z=O, S, Se, or Te 29,[47][48][49][50][51]. Other noteworthy compounds in the region are the LnSbTe family (Ln = lanthanide) [52][53][54][55]. On the zone border lies the topological superconductor UTe 2 [56][57][58].…”

Symmetry-enforced band crossings in trigonal materials: Accordion states and Weyl nodal lines

“…Here, we extend this analysis to trigonal systems. There has been a number of previous works, which considered specific types of nonsymmorphic band crossings [15,[33][34][35] and proposed candidate materials, where these are realized [39][40][41][42]. However, a comprehensive classification of all possible nonsymmorphic bandcrossings in trigonal materials has not been performed before.…”