Electronic states in superconducting type-II Dirac semimetal: 1T-PdSeTe

TL;DR

This study investigates the electronic structures and superconducting properties of 1T-PdSeTe, revealing topological surface states, a higher transition temperature compared to similar compounds, and the influence of chemical pressure on superconductivity.

Contribution

It provides new insights into how atomic disorder and chemical pressure affect the electronic states and superconductivity in 1T-PdSeTe, a type-II Dirac semimetal.

Findings

Superconducting transition temperature is 3.2 K, nearly twice that of 1T-PdTe2.

Topological surface states are confirmed via ARPES and DFT calculations.

Band structures are similar to 1T-PdTe2 despite atomic disorder.

Abstract

We have investigated the surface and bulk electronic structures of the superconducting type-II Dirac semimetal 1T-PdSeTe. The superconducting transition temperature $T_C = 3.2$ K was almost twice as high as $T_C = 1.6$ K in 1T-PdTe$_2$. Scanning transmission electron microscopy measurements showed homogeneously mixed Se and Te atoms in the chalcogen layers, consistent with the CdI$_2$-type crystal structure. Angle-resolved photoemission spectroscopy measurements and density functional theory calculations indicated the existence of the topological surface states, and the overall band structures were similar to those of 1T-PdTe$_2$. These results suggest that CdI$_2$-type lattice symmetry dictates the band dispersion, regardless of atomic disorder in the chalcogen layers. As the electronic band dispersion and the local structures were persistent upon substitution, the enhancement of $T_C$ is likely associated with the chemical pressure. Our results provide insight into the effects of the solid solution on the surface and bulk electronic states as well as the superconducting transition temperature.