Photoemission Spectroscopy and the Unusually Robust One Dimensional Physics of Lithium Purple Bronze

TL;DR

This study uses temperature-dependent photoemission spectroscopy to investigate the robust one-dimensional physics in lithium purple bronze, revealing characteristic Luttinger liquid behaviors and quantum critical scaling near the superconducting transition.

Contribution

It provides evidence for persistent one-dimensional Luttinger liquid features in Li0.9Mo6O17 down to the superconducting transition, with analysis of deviations from ideal models.

Findings

Observation of power law spectral behavior above Tc

Detection of holon and spinon features in lineshapes

Identification of quantum critical scaling in lineshapes

Abstract

Temperature dependent photoemission spectroscopy in Li0.9Mo6O17 contributes to evidence for one dimensional physics that is unusually robust. Three generic characteristics of the Luttinger liquid are observed, power law behavior of the k-integrated spectral function down to temperatures just above the superconducting transition, k-resolved lineshapes that show holon and spinon features, and quantum critical (QC) scaling in the lineshapes. Departures of the lineshapes and the scaling from expectations in the Tomonaga Luttinger model can be partially described by a phenomenological momentum broadening that is presented and discussed. The possibility that some form of 1d physics obtains even down to the superconducting transition temperature is assessed.