Possible evidence of non-Fermi liquid behavior from quasi-one-dimensional indium nanowires

TL;DR

This study presents experimental evidence of non-Fermi liquid behavior in quasi-one-dimensional indium nanowires at room temperature, observed through plasmon dispersion measurements that align with NFL theory predictions.

Contribution

First direct measurement of plasmon dispersion in In nanowires showing NFL characteristics, highlighting non-analytic width dispersion consistent with NFL theory.

Findings

Energy-momentum dispersion matches NFL predictions at low q

Width dispersion follows a non-analytic power law with exponent ~1.4

Evidence of NFL behavior despite suppressed spin-charge separation

Abstract

We report possible evidence of non-Fermi liquid (NFL) observed at room temperature from the quasi one-dimensional (1D) indium (In) nanowires self-assembled on Si(111)-7$\times$7 surface. Using high-resolution electron-energy-loss spectroscopy, we have measured energy and width dispersions of a low energy intrasubband plasmon excitation in the In nanowires. We observe the energy-momentum dispersion $\omega$(q) in the low q limit exactly as predicted by both NFL theory and the random-phase-approximation. The unusual non-analytic width dispersion $\zeta(q) \sim q^{\alpha}$ measured with an exponent ${\alpha}$=1.40$\pm$0.24, however, is understood only by the NFL theory. Such an abnormal width dispersion of low energy excitations may probe the NFL feature of a non-ideal 1D interacting electron system despite the significantly suppressed spin-charge separation ($\leq$40 meV).