Charge density wave induced nodal lines in LaTe.

LaTe is a non-centrosymmetric material with time reversal symmetry, where the charge density wave is hosted by the Te bilayers. Here, we show that LaTe hosts a Kramers nodal line-a twofold degenerate nodal line connecting time reversal-invariant momenta. We use angle-resolved photoemission spectroscopy, density functional theory with an experimentally reported modulated structure, effective band structures calculated by band unfolding, and symmetry arguments to reveal the Kramers nodal line.

Probing the martensite transition and thermoelectric properties of CoTa(Si, Ge, Sn and1, 2): a study based on density functional theory.

In this work, using density functional theory based electronic structure calculations, we carry out a comparative study of geometric, mechanical, electronic, magnetic, and thermoelectric properties of CoTaalloys, where= Si, Ge and Sn and= 1 and 2. In the present study, a systematic approach has been taken to perform calculations to probe the possibility of existence of a tetragonal (martensite) phase in these alloys and also to perform a comparative study of various physical properties of the six systems, mentioned above, in the cubic and possible tetragonal phases. From our calculations, a tetragonal phase has been found to be stable up to about 400 K in case of CoTaSi and CoTaGe alloys, and up to about 115 K for CoTaSn, indicating the presence of room temperature cubic phase in the latter alloy unlike the former two.