Chaotic Dirac billiard in graphene quantum dots.
The exceptional electronic properties of graphene, with its charge carriers mimicking relativistic quantum particles and its formidable potential in various applications, have ensured a rapid growth of interest in this new material. We report on electron transport in quantum dot devices carved entirely from graphene. At large sizes (>100 nanometers), they behave as conventional single-electron transistors, exhibiting periodic Coulomb blockade peaks. For quantum dots smaller than 100 nanometers, the peaks become strongly nonperiodic, indicating a major contribution of quantum confinement. Random peak spacing and its statistics are well described by the theory of chaotic neutrino billiards. Short constrictions of only a few nanometers in width remain conductive and reveal a confinement gap of up to 0.5 electron volt, demonstrating the possibility of molecular-scale electronics based on graphene.
Ponomarenko
L A
LA
Manchester Centre for Mesoscience and Nanotechnology, University of Manchester, Manchester M13 9PL, UK.
Schedin
F
F
Katsnelson
M I
MI
Yang
R
R
Hill
E W
EW
Novoselov
K S
KS
Geim
A K
AK