Superconducting and structural properties of the type-I superconductor PdTe2 under high pressure

Abstract

The transition metal dichalcogenide PdTe 2 has attractive features based on its classification as a type-II Dirac semimetal and the occurrence of type-I superconductivity, providing a platform for discussion of a topological superconductor. Our recent work revealed that type-I superconductivity persists up to pressures of ∼2.5 GPa and the superconducting transition temperature T c reaches a maximum at around 1 GPa, which is inconsistent with the theoretical prediction. To understand its nonmonotonic variation and investigate superconductivity at higher pressures, we performed structural analysis by x-ray diffraction at room temperature below 8 GPa and electrical resistivity measurements at low temperatures from 1 to 8 GPa. With regard to the superconductivity beyond 1 GPa, the monotonic decrease in T c is reproduced without any noticeable anomalies; T c changes from 1.8 K at 1 GPa to 0.82 K at 5.5 GPa with dT c /dP ∼ −0.22 K/GPa. The crystal structure with space group P 3m1 is stable in the pressure range we examined. On the other hand, the normalized pressure-strain analysis (finite strain analysis) indicates that the compressibility changes around 1 GPa, suggesting that a Lifshitz transition occurs. We here discuss the effect of pressure on the superconducting and structural properties based on the comparison of these experimental results.

Protonation enhanced superconductivity in PdTe2

“…Combing the superconductivity and the topological nontrivial band structure, PdTe 2 is considered as a topological superconductor candidate. Pressure experiments showed that the superconducting transition temperature decreases from 1.8 K at 1 GPa to 0.82 K at 5.5 GPa [25,26]. First-principle calculations predicted a new pair of type-I Dirac cone emerges at 4.7 GPa and the coexistence of type-I and type-II Dirac cones under proper pressure (4.7 GPa-6.1 GPa) [27].…”

Pressure‐Induced Superconductivity and Topological Quantum Phase Transitions in the Topological Semimetal ZrTe2

“…[22,38] The application of pressure can effectively tune the crystal structures and the corresponding electronic states in a valid and systematic fashion, and its related studies on MX 2 , indeed, have given rise to many novel physical phenomena. [23,[39][40][41][42][43][44] To date, the high-pressure properties of ZrTe 2 have not been well explored. Here, we systematically explore the structure and electronic properties of topological TMDC ZrTe 2 single crystal under high pressure.…”

Disorder induced transition from type-I to type-II superconductivity in the Dirac semimetal PdTe$_2$

“…Finally, evidence for bulk type-I superconductivity was attained through heat capacity measurements by demonstrating the presence of latent heat [12]. Measurements under hydrostatic pressure show that superconductivity is still present at 5.5 GPa [26] and remains of the first kind at least till 2.5 GPa [27].…”