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TT: Fachverband Tiefe Temperaturen
TT 18: Superconductivity: Poster
TT 18.6: Poster
Monday, March 18, 2024, 15:00–18:00, Poster C
3D van Hove singularities near the Fermi level in NiTe2 and PdTe2 — •Emily C. McFarlane1, Jonas A. Krieger2, Antonio Sanna1, Camilla Pellegrini1, Mihir Date1, Gabriele Domaine1, Banabir Pal1, Pranava K. Sivakumar1, Anirban Chakraborty1, Stuart S. P. Parkin1, and Niels B. M. Schröter1 — 1Max Planck Institute of Microstructure Physics Weinberg 2, 06120 Halle, Germany — 2Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
The type-II Dirac semimetal NiTe2 has been used as the non-superconducting barrier in devices demonstrating the Josephson diode effect (JDE) at 20mK [1]. However from the Allen-Dynes formula, NiTe2 is estimated to have a Tc of 1.5K [2]. In isostructural PdTe2, a saddle-point van Hove singularity (vHs) and its proximity to the Fermi level (EF) is thought to be important for its type-I superconductivity with Tc=1.7K [3]. We investigated the electronic band structure of NiTe2 and PdTe2 to understand the lack of superconductivity in NiTe2 and origin of the JDE.
We present soft X-ray ARPES measurements of the bulk band structure to confirm the location of this vHs in NiTe2 and PdTe2, and show that it is closer to EF in NiTe2. We also present a new approach to superconducting-DFT calculations which suggests a magnetic instability is responsible for suppressing superconductivity in NiTe2.
[1] B. Pal et al. Nature Physics 18 1228-1233 (2022).
[2] J. Zhang, G. Q. Huang J. Phys.: Condens. Matter 32 205702 (2020)
[3] K. Kim et al. Phys. Rev. B 97 165102 (2018).
Keywords: ARPES; van Hove singularities; Josephson Diode Effect; superconductivity