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

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arXiv · 1203.6672

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

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Abstract

The upper critical field $H_{c2}$ 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, $H_{c2}$ increases monotonically with decreasing temperature to a value five times larger than the estimated paramagnetic pair-breaking field. Theories for the enhancement of $H_{c2}$ 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.

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J. -F. Mercure, A. F. Bangura, Xiaofeng Xu, N. Wakeham, A. Carrington, P. Walmsley, M. Greenblatt, N. E. Hussey. 2012-03-29. Superconducting critical field far above the Pauli limit in one-dimensional Li$_{0.9}$Mo$_6$O$_{17}$. https://arxiv.org/abs/1203.6672

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