I study condensed
matter physics using theoretical
methods. What brought me to
this specialty was my fascination
with statistical physics, from which we can learn an amazing
amount about a system containing
many particles from only a few assumptions.
Dirac Fermions
My graduate work is on two dimensional
systems of "Dirac
Fermions." Dirac Fermions are electrons (or holes) which have
an energy (E) to momentum (p) relationship which is linear (E=vp) rather
than the typical quadratic (E=p2/2m) one. Although it doesn't sound too
spectacular, condensed matter systems which have these types of
particles have some very interesting properties. My phd thesis work focuses on
the electrical properties of two such systems:
- Graphene is a layer of graphite (carbon) just one atom thick!
- Topological insulators are three dimensional materials, but they
have some electrons which are stuck nearby to the surfaces and obey the
Dirac Fermion energy-momentum relationship.
Why study these systems? Besides offering the chance to
explore unknown physics, these materials both have potential for
important applications. Graphene shows promise as
the material for future electronic devices, and
topological insulators may be useful for quantum computation.
My work is supported by the Penn State Center for Nanoscale Science (CNS), which is an NSF MRSEC. One goal of the CNS is to understand
electronic properties of confined systems, including two-dimensional systems such
as graphene and the topological insulator surface state.
Publications
- Duming Zhang, Jian Wang, Ashley M. DaSilva, Joon Sue Lee, Humberto
R. Gutierrez, Moses H. W. Chan, Jainendra K. Jain, and Nitin Samarth,
Evidence for the superconducting proximity effect and Pearl vortices in
a candidate topological insulator Physical Review B
(2011). (arXiv:1106.3605)
- Ashley M. DaSilva, The stability of the fractional quantum Hall effect in topological insulators, Solid State Communications, 2011 (arXiv:1106.4418)
- Ashley M. DaSilva, Milton W. Cole, Effects of Physically Adsorbed Films on Conductivity of Two-Dimensional Metal Surfaces and Graphene, Journal of Low Temperature Physics, 2011
- Jian Wang, Ashley M DaSilva, Cui-Zu Chang, Ke He, J K Jain, Nitin Samarth, Xu-Cun Ma, Qi-Kun Xue, Moses H W Chan, Evidence for electron-electron interaction in topological insulator thin films, Physical Review B, 2011 (arXiv:1012.0271)
- Ashley M. DaSilva, Ke Zou, Jainendra K. Jain, and Jun Zhu, Mechanism for Current Saturation and Energy Dissipation in Graphene Transistors, Physical Review Letters, 2010 (arXiv:1005.1351)
