[Back]

E. Gruber, R. Wilhelm, R. Pétuya, V. Smejkal, R. Kozubek, A. Hierzenberger, B. Beyer, I. Aldazabal, A. Kazansky, F. Libisch, A. Krasheninnikov, M. Schleberger, S. Fascko, A. Borisov, A. Arnau, F. Aumayr:
"Ultrafast electronic response of graphene to a strong and localized electric field";
Nature Communications, 7 (2016), 13948; 1 - 7.

The way conduction electrons respond to ultrafast external perturbations in low dimensional
materials is at the core of the design of future devices for (opto)electronics, photodetection
and spintronics. Highly charged ions provide a tool for probing the electronic response of
solids to extremely strong electric fields localized down to nanometre-sized areas. With ion
transmission times in the order of femtoseconds, we can directly probe the local electronic
dynamics of an ultrathin foil on this timescale. Here we report on the ability of freestanding
single layer graphene to provide tens of electrons for charge neutralization of a slow highly
charged ion within a few femtoseconds. With values higher than 1012Acm 2, the resulting
local current density in graphene exceeds previously measured breakdown currents by three
orders of magnitude. Surprisingly, the passing ion does not tear nanometre-sized holes into
the single layer graphene. We use time-dependent density functional theory to gain insight
into the multielectron dynamics.

http://dx.doi.org/10.1038/ncomms13948