Research Accomplishments
Since 1990, I have been researching problems which fall under the
classification of "the theory of the electronic and optical properties
of semiconductors."
A list of my most significant contributions follow.
- Silicene
In 2007, my student Gian Guzman-Verri and I were the first to
predict that a two-dimensional form of silicon we named silicene
would have properties identical to graphene.
Since 2010, there have been reports of the fabrication of silicene
and it is now predicted to challenge graphene for material dominance!
See the following reports for more information:
- Prediction of in-plane birefringence of asymmetric quantum
wells grown in the [001] direction (1998).
Many groups have grown and investigated the optical properties of
quantum wells since the invention of the MBE in the 1970s.
The fact that those structures display in-plane birefringence
has escaped attention until my 1998 paper in Applied Physics
Letters.
The effect has since been verified experimentally by the group
of Prof. Dr. Cardona at the Max-Planck Institut für
Festkörperphysik and in porous Si films by the group of
Laine in Finland.
- Did the first calculation to prove, and among the
first to predict, that normally-incident light can be absorbed
by n-doped zincblende quantum wells grown along the [001]
direction (1995,1996).
This possibility could revolutionize the design of optoelectronic
devices such as photodetectors.
This work has also corrected many misconceptions in the experimental
and theoretical work of the group of Fonstad at MIT.
- I provided the first formal and general proof that the
dielectric tensor of a zincblende crystal cannot have a linear
term in the wavevector (1994).
In effect, it was the first microscopic proof of Onsager's relation
for a nonmagnetic crystal.
This has not only important practical consequences regarding the
propagation of polarized light through zincblende crystals
but also has fundamental consequences on the time reversibility
of the matter-light interaction.
This work has debunked claims of new physics in 5+ papers
in reputable peer-reviewed journals by the experimental group of
Zheludev at the University of Southampton.
- Developing the formalism for calculating the optical properties
of crystalline solids using the empirical tight-binding method (1993).
The empirical tight-binding method (ETBM) was developed in 1954 by
Slater and Koster to calculate the electronic band structure of
crystals. Up until my work, most of the subsequent experts have
professed not knowing how to calculate optical properties using this
technique.
My 1993 paper has, so far, resulted in over 90 direct citations.
My formalism has been employed by others to study systems as diverse as
the collapse of solid C60 to the excitons in Si
nanocrystals.
Research Collaborators