Chiral Superconductivity in Heavy-Fermion Metal UTe2

Published

March 24, 2020

Author(s)

Lin Jiao, Sean Howard

Abstract

Spin-triplet superconductivity is a condensate of electron pairs with spin-1 and an odd parity pair wavefunction¹. A particularly interesting manifestation of triplet pairing is a chiral p-wave state which is topologically non-trivial and a natural platform for realizing Majorana edge modes^2,3. Triplet pairing is however rare in solid state systems and so far, no unambiguous identification has been made in any bulk compound. Since pairing is most naturally mediated by ferromagnetic spin fluctuations, uranium based heavy fermion systems containing felectron elements that can harbor both strong correlations and magnetism are considered ideal candidate spin-triplet superconductors^4-10. In this work we present scanning tunneling microscopy (STM) studies of the newly discovered heavy fermion superconductor, UTe₂ with a T_SC of 1.6 K¹¹. We find signatures of coexisting Kondo effect and superconductivity which show competing spatial modulations within one unit-cell. STM spectroscopy at step edges oriented at 0 °- and 45 ° with respect to the a-axis show signatures of chiral in-gap states, predicted to exist on the boundary of a topological superconductor, which have not been observed to date. Combined with existing data indicating triplet pairing, the presence of chiral edge states suggests that UTe₂ is a strong candidate material for chiral-triplet topological superconductivity.

Citation

Nature

Volume

579

Pub Type

Journals

Download Paper

DOI Link

Keywords

superconductivity

Citation

Jiao, L. and Howard, S. (2020), Chiral Superconductivity in Heavy-Fermion Metal UTe₂, Nature, [online], https://doi.org/10.1038/s41586-020-2122-2 (Accessed April 23, 2024)