Colloquium: Prof. Andrei Kryjevski

Andrei Kryjevski
Department of Physics, North Dakota State University

Aspects of the Dynamics of Strongly Interacting Fermions:
from Unitary Fermi Gas to Multiple Exciton Generation in Silicon Nanoparticles

Friday, March 14, 2014 4:01pm-4:50pm

An analytical technique similar to the epsilon expansion in the theory of critical
phenomena has been proposed for dilute Fermi gas with two body interactions
characterized by infinite scattering length and zero effective range which is called
Unitary Fermi Gas (Nishida and Son, Phys.Rev.Lett.97:050403, 2006). After an
introduction of the technique, some calculation results will be described: 1. superfluid
vortex structure, 2. low energy density-density correlation function, 3. shear viscosity in
the normal phase.

In the second part, we will discuss multiple exciton generation (MEG), or carrier
multiplication, calculations in several silicon nanoparticles, such as nm-sized Si quantum
dots (QDs) with crystalline and amorphous core structures, the arrays constructed from
these QDs, as well as crystalline and amorphous Si nanowires. The calculations are based
on Density Functional Theory (DFT) combined with the many body perturbation theory.
Amorphous Si nanostructures are predicted to have more effective carrier multiplication
at lower energy.