Possible evidence of non-Fermi liquid behaviour from Quasi-one-dimensional indium nanowires

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 x 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) similar to q(alpha) measured with an exponent alpha = 1.40 +/- 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 (<= 40 meV).