Intertwining bulk and surface: the case of UTe$_2$

Abstract

UTe$_2$ has been the focus of numerous experimental and theoretical studies in recent years, as it is recognized as an odd-parity bulk superconductor. Its surface has also been probed, revealing charge density wave (CDW), pair density wave (PDW), and time-reversal symmetry breaking (TRSB). In this work, we propose that the interplay between the order parameters observed on the surface and in the bulk of UTe$_2$ may be crucial in explaining some of the unusual features detected by surface probes in this material. Through a phenomenological analysis, we can account for three distinctive experimental signatures observed on the surface of UTe$_2$: i) the apparent suppression of CDW order at the upper critical field of the bulk superconducting state; ii) the magnetic field-induced imbalance of the Fourier peaks associated with the CDW; iii) the onset of TRSB at the bulk superconducting critical temperature and its field-trainability. Furthermore, we propose specific experimental checks to validate our conjecture, which we believe could be promptly achieved.