Evidence for two dimensional anisotropic Luttinger liquids at millikelvin temperatures.

Yu, Guo; Wang, Pengjie; Uzan-Narovlansky, Ayelet J; Jia, Yanyu; Onyszczak, Michael; Singha, Ratnadwip; Gui, Xin; Song, Tiancheng et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

Interacting electrons in one dimension (1D) are governed by the Luttinger liquid (LL) theory in which excitations are fractionalized. Can a LL-like state emerge in a 2D system as a stable zero-temperature phase? This question is crucial in the study of non-Fermi liquids. A recent experiment identified twisted bilayer tungsten ditelluride (tWTe<sub>2</sub>) as a 2D host of LL-like physics at a few kelvins. Here we report evidence for a 2D anisotropic LL state down to 50 mK, spontaneously formed in tWTe<sub>2</sub> with a twist angle of ~ 3<sup>o</sup>. While the system is metallic-like and nearly isotropic above 2 K, a dramatically enhanced electronic anisotropy develops in the millikelvin regime. In the anisotropic phase, we observe characteristics of a 2D LL phase including a power-law across-wire conductance and a zero-bias dip in the along-wire differential resistance. Our results represent a step forward in the search for stable LL physics beyond 1D.