Superconducting critical field far above the Pauli limit in one-dimensional Li$_{0.9}$Mo$_6$O$_{17}$

J. -F. Mercure; A. F. Bangura; Xiaofeng Xu; N. Wakeham; A. Carrington; P. Walmsley; M. Greenblatt; N. E. Hussey

paper

Superconducting critical field far above the Pauli limit in one-dimensional Li $_{0.9}$ Mo $_{6}$ O $_{17}$

arXiv:1203.6672

Abstract

The upper critical field $H_{c 2}$ of purple bronze Li $_{0.9}$ Mo $_{6}$ O $_{17}$ is found to exhibit a large anisotropy, in quantitative agreement with that expected from the observed electrical resistivity anisotropy. With the field aligned along the most conducting axis, $H_{c 2}$ increases monotonically with decreasing temperature to a value five times larger than the estimated paramagnetic pair-breaking field. Theories for the enhancement of $H_{c 2}$ invoking spin-orbit scattering or strong-coupling superconductivity are shown to be inadequate in explaining the observed behavior, suggesting that the pairing state in Li $_{0.9}$ Mo $_{6}$ O $_{17}$ is unconventional and possibly spin-triplet.

9 pages, 4 Main Figures, 5 Supplementary Information Figures; Accepted for publication in Physical Review Letters

Superconducting critical field far above the Pauli limit in one-dimensional Li0.9​Mo6​O17​

Abstract

Superconducting critical field far above the Pauli limit in one-dimensional Li $_{0.9}$ Mo $_{6}$ O $_{17}$