Electron-phonon interaction and point contact enhanced superconductivity in trigonal PtBi2

Abstract

PtBi2 is a Weyl semimetal, which demonstrates superconductivity with low critical temperature Tc ~ 0.6 K in the bulk. Here, we report our study of electron-phonon interaction (EPI) in trigonal PtBi2 by the Yanson point contact (PC) spectroscopy and presenting the observation of PC enhanced superconductivity. We show, that the Yansons PC spectra display a broad maximum around 15 meV, indicating, apparently, EPI mechanism of Cooper pairing in PtBi2. Moreover, we discovered a substantial increase of Tc up to ~ 3.5 K in PCs. The observed Tc is sufficiently higher than the bulk value, as well as detected at hydrostatic pressure. We calculated the phonon density of states and Eliashberg EPI function in PtBi2 within the framework of the density functional theory. A comparison of experimental data with theoretical calculations showed acceptable agreement. The theoretical Tc is 3.5 K, which corresponds to the experimental value.

13 pages, 4 figs, with supplement. Submitted to Low Temp. Phys. (Fiz. Nizk. Temp.)

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• Enhanced weak superconductivity in trigonal $\gamma$-PtBi${}_2$
• Phonon-mediated intrinsic topological superconductivity in Fermi arcs
• Ginzburg-Landau theory for unconventional surface superconductivity in PtBi${}_2$
• Interplay between inversion and translation symmetries in trigonal PtBi${}_2$
• Atomic Visualization of Bulk and Surface Superconductivity in Weyl Semimetal γ-PtBi2
• Mechanism for Nodal Topological Superconductivity on PtBi${}_2$ Surface