Unusual renormalization group (RG) flow and temperature-dependent phase transition in strongly-insulating monolayer epitaxial graphene

Lung I. Huang, Yanfei Yang, Chieh Wen Liu, Randolph E. Elmquist, Shun-Tsung Lo*, Fan Hung Liu, Chi Te Liang

*Corresponding author for this work

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

By changing the measurement temperature (T), one can vary the effective sample size so as to study the renormalization group (RG) (or T-driven) flow of a semiconductor, a topological insulator, or a graphene device in the complex conductivity plane. Here we report RG flow of large-area, strongly disordered monolayer graphene epitaxially grown on SiC, which becomes insulating as T decreases for zero magnetic field. We observe cusp-like RG flow towards (σxy = e2/h, σxx = e2/h) where σxy and σxx are Hall conductivity and diagonal conductivity respectively. Such features, indicative of a fixed-temperature phase transition, have never been observed before and cannot be explained by existing RG models based on a modular symmetry group. Therefore, our results suggest the need for new theoretical models and experimental study leading to an understanding of strongly disordered two-dimensional materials such as graphene, few-layer black phosphorus, WSe2, and so on.

Original languageEnglish
Pages (from-to)31333-31337
Number of pages5
JournalRSC Advances
Volume7
Issue number50
DOIs
StatePublished - 1 Jan 2017

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