Revealing a 3D Fermi Surface Pocket and Electron-Hole Tunneling in UTe$_{2}$ with Quantum Oscillations

TL;DR

This study provides the first experimental evidence of a 3D Fermi surface pocket in UTe$_{2}$ and observes electron-hole tunneling, enhancing understanding of its superconducting and topological properties.

Contribution

It reports the first detection of a 3D Fermi surface pocket in UTe$_{2}$ using quantum oscillations, confirming theoretical predictions and revealing electron-hole tunneling phenomena.

Findings

Identification of a small, isotropic 3D Fermi surface pocket

Observation of high-frequency quantum oscillations from electron-hole tunneling

Coexistence of 2D and 3D Fermi surface pockets

Abstract

Spin triplet superconductor UTe$_{2}$ is widely believed to host a quasi-two-dimensional Fermi surface, revealed by first principal calculations, photoemission and quantum oscillation measurements. An outstanding question still remains as to the existence of a three-dimensional Fermi surface pocket, which is crucial for our understanding of the exotic superconducting and topological properties of UTe$_{2}$. This 3D Fermi surface pocket appears in various theoretical models with different physics origins but has not been detected experimentally. Here for the first time, we provide concrete evidence for a relatively isotropic, small Fermi surface pocket of UTe$_{2}$ via quantum oscillation measurements. In addition, we observed high frequency quantum oscillations corresponding to electron-hole tunneling between adjacent electron and hole pockets. The coexistence of 2D and 3D Fermi surface pockets, as well as the breakdown orbits, provides a test bed for theoretical models and aid the realization of a unified understanding of superconducting state of UTe$_{2}$ from the first-principles approach.