Microscopic origins of the terahertz carrier relaxation and cooling dynamics in graphene
Journal article, 2016

The ultrafast dynamics of hot carriers in graphene are key to both understanding of fundamental carrier-carrier interactions and carrier-phonon relaxation processes in two-dimensional materials, and understanding of the physics underlying novel high-speed electronic and optoelectronic devices. Many recent experiments on hot carriers using terahertz spectroscopy and related techniques have interpreted the variety of observed signals within phenomenological frameworks, and sometimes invoke extrinsic effects such as disorder. Here, we present an integrated experimental and theoretical programme, using ultrafast timeresolved terahertz spectroscopy combined with microscopic modelling, to systematically investigate the hot-carrier dynamics in a wide array of graphene samples having varying amounts of disorder and with either high or low doping levels. The theory reproduces the observed dynamics quantitatively without the need to invoke any fitting parameters, phenomenological models or extrinsic effects such as disorder. We demonstrate that the dynamics are dominated by the combined effect of efficient carrier-carrier scattering, which maintains a thermalized carrier distribution, and carrier-optical-phonon scattering, which removes energy from the carrier liquid.

Author

M. T. Mihnev

Faris Kadi

C. J. Divin

T. Winzer

SangWook Lee

C. H. Liu

Z. Zhong

Christian Berger

W. A. de Heer

Ermin Malic

Chalmers, Physics, Condensed Matter Theory

A. Knorr

T. B. Norris

Nature Communications

2041-1723 (ISSN)

Vol. 7

Graphene-Based Revolutions in ICT And Beyond (Graphene Flagship)

European Commission (FP7), 2013-10-01 -- 2016-03-31.

Subject Categories

Condensed Matter Physics

DOI

10.1038/ncomms11617

PubMed

27221060

More information

Created

10/8/2017