Electron-phonon decoupling in disordered graphene

Many body localisation [1] (MBL) in a solid state system has felt like a distant goal for many years, experimental evidence for this non-ergodic state has only been seen in ultra cold atomic systems[2]. The fundamental problem with solid state MBL systems is that introducing disorder increases interactions with the very phonons that destroy MBL. Recent work by Lerner et al. [3] predicts that there should be a break down in the electron-phonon coupling in most conductors with enough disorder and low enough temperatures. In this work carbons are removed from a graphene lattice to make point like static scattering sites using a focussed Helium ion beam. This method allows a high level of control so that the disorder introduced can be tailored to access this electron-phonon decoupling regime at experimentally available temperatures. The decoupling manifests as large hysteretic jumps in the current voltage characteristics indicating a large range of disallowed electron temperatures. While these results do not directly indicate the presence of MBL it would be impossible to have such a system without.

[1] D. M. Basko, I. L. Aleiner, & B. L. Altshuler, Annals of Physics. 321 (2006): 1126–1205. DOI:10.1016/j.aop.2005.11.014

[2] J. Sous & E. Grant, PRL 120, 110601 (2018). DOI: 10.1103/PhysRevLett.120.110601

[3] G. McArdle & I. V. Lerner, Scientific Reports 11, 24293 (2021). DOI:10.1038/s41598-021-03668-z