en
Scientific article
Open access
English

Breakdown of the Migdal approximation at Lifshitz transitions with giant zero-point motion in the H3S superconductor

Published inScientific reports, vol. 6, 24816
Publication date2016
Abstract

While 203 K high temperature superconductivity in H3S has been interpreted by BCS theory in the dirty limit here we focus on the e ects of hydrogen zero-point-motion and the multiband electronic structure relevant for multigap superconductivity near Lifshitz transitions. We describe how the topology of the Fermi surfaces evolves with pressure giving di erent Lifshitz-transitions. A neck-disrupting Lifshitz- transition (type 2) occurs where the van Hove singularity, vHs, crosses the chemical potential at 210 GPa and new small 2D Fermi surface portions appear with slow Fermi velocity where the Migdal- approximation becomes questionable. We show that the neglected hydrogen zero-point motion ZPM, plays a key role at Lifshitz transitions. It induces an energy shift of about 600 meV of the vHs. The other Lifshitz-transition (of type 1) for the appearing of a new Fermi surface occurs at 130 GPa where new Fermi surfaces appear at the Γ point of the Brillouin zone here the Migdal-approximation breaks down and the zero-point-motion induces large uctuations. The maximum Tc = 203 K occurs at 160 GPa where EF/ω0 = 1 in the small Fermi surface pocket at Γ. A Feshbach-like resonance between a possible BEC-BCS condensate at Γ and the BCS condensate in di erent k-space spots is proposed.

Research group
Citation (ISO format)
JARLBORG, Thomas N., BIANCONI, Antonio. Breakdown of the Migdal approximation at Lifshitz transitions with giant zero-point motion in the H<sub>3</sub>S superconductor. In: Scientific reports, 2016, vol. 6, p. 24816. doi: 10.1038/srep24816
Main files (1)
Article (Published version)
accessLevelPublic
Identifiers
ISSN of the journal2045-2322
458views
172downloads

Technical informations

Creation09/27/2016 3:11:00 PM
First validation09/27/2016 3:11:00 PM
Update time03/15/2023 12:46:58 AM
Status update03/15/2023 12:46:58 AM
Last indexation01/16/2024 9:53:34 PM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack