Gapped electron fractionalization in robustly one dimensional Li0.9Mo6O17

TL;DR

This paper investigates the complex electron behavior in quasi-one-dimensional Li0.9Mo6O17, revealing a gapped antisymmetric charge mode that explains deviations from the standard Tomonaga-Luttinger model and influences its low-temperature properties.

Contribution

It introduces a model accounting for four modes from two bands, with a gapped antisymmetric charge mode, explaining experimental deviations and the resistivity upturn in Li0.9Mo6O17.

Findings

The antisymmetric charge mode is gapped near 25K.

The gap explains the resistivity upturn without charge or spin density wave formation.

The system remains non-Fermi liquid down to 1.9K, close to superconductivity.

Abstract

The angle resolved photoemission spectroscopy lineshapes of quasi one-dimensional (1d) Li0.9Mo6O17 display both agreement with and departures from the one-band Tomonaga-Luttinger model. We show that the departures can be understood by explicitly accounting for the four modes arising from the two quasi-1d bands known to cross the Fermi energy. The key assumption is that the antisymmetric charge mode is gapped with a magnitude near the temperature (T) of a mysterious 25K powerlaw resistivity upturn. The gap is consistent with the lack of a charge or spin density wave accompanying the upturn, is able to control the upturn T, and prevents crossover to a Fermi liquid (FL) down to the superconducting transition at 1.9K.