Quantum oscillations and a non-trivial Berry phase in the noncentrosymmetric superconductor BiPd

TL;DR

This study reveals complex Fermi surface features and a non-trivial Berry phase in BiPd, indicating topological states that could lead to topological superconductivity in this noncentrosymmetric superconductor.

Contribution

It provides the first detailed measurement of quantum oscillations and Berry phase in BiPd, highlighting its topological properties and potential for topological superconductivity.

Findings

Identification of multiple Fermi surface sheets

Detection of a non-trivial $$-Berry phase in a small pocket

Evidence supporting topological states in bulk BiPd

Abstract

We report the measurements of de Haas-van Alphen (dHvA) oscillations in the noncentrosymmetric superconductor BiPd. Several pieces of a complex multi-sheet Fermi surface are identified, including a small pocket (frequency 40 T) which is three dimensional and anisotropic. From the temperature dependence of the amplitude of the oscillations, the cyclotron effective mass is ($0.18$ $\pm$ 0.1) $m_e$. Further analysis showed a non-trivial $\pi$-Berry phase is associated with the 40 T pocket, which strongly supports the presence of topological states in bulk BiPd and may result in topological superconductivity due to the proximity coupling to other bands.