학술논문
Out-of-equilibrium criticalities in graphene superlattices
Document Type
Academic Journal
Author
Berdyugin, Alexey I.; Xin, Na; Gao, Haoyang; Slizovskiy, Sergey; Dong, Zhiyu; Bhattacharjee, Shubhadeep; Kumaravadivel, P.; Xu, Shuigang; Ponomarenko, L.A.; Holwill, Matthew; Bandurin, D.A.; Kirn, Minsoo; Cao, Yang; Greenaway, M.T.; Novoselov, K.S.; Grigorieva, I.V.; Watanabe, K.; Taniguchi, T.; Falko, V.I.; Levrtov, L.S.; Kumar, Roshan Krishna; Geim, A.K.
Source
Science. January 28, 2022, Vol. 375 Issue 6579, p430, 4 p.
Subject
Language
English
ISSN
0036-8075
Abstract
In thermodynamic equilibrium, current in metallic systems is carried by electronic states near the Fermi energy, whereas the filled bands underneath contribute little to conduction. Here, we describe a very different regime in which carrier distribution in graphene and its superlattices is shifted so far from equilibrium that the filled bands start playing an essential role, leading to a critical-current behavior. The criticalities develop upon the velocity of electron flow reaching the Fermi velocity. Key signatures of the out-of-equilibrium state are current-voltage characteristics that resemble those of superconductors, sharp peaks in differential resistance, sign reversal of the Hall effect, and a marked anomaly caused by the Schwinger-like production of hot electron-hole plasma. The observed behavior is expected to be common to all graphene-based superlattices.