Thermoelectric Properties of Fe0.2Co3.8Sb12-xTex ... - Physics

Evolution of fermionic superfluid across the crossover from three to two dimensions
Sudeep Kumar Ghosh ∗ and Vijay B. Shenoy †
Centre for Condensed Matter Theory, Department of Physics,
Indian Institute of Science, Bangalore 560 012, India
Motivated by recent experiments on the evolution of fermionic superfluid pairing from three to two
dimensions, we construct and study a Bogoliubov-de Gennes theory that accurately accounts for the
periodic potential that induces this dimensional crossover. We consider a system of spin- 1 2 fermions
interacting in the singlet channel via a contact interaction confined by an optical lattice potential
in the z-direction and the motion in plane is free. With the increase in potential depth, the system
gets divided into stacks of two dimensional layers with gradually decreasing inter layer hopping.
The mean field equations are solved numerically to obtain the Bloch bands. For small potential
depth, the linear response of density and pairing gap of the system are obtained numerically and
compared with that of perturbation theory calculations. In deep lattice limit the system becomes
two dimensional and the binding energy is found to be in close agreement with the two dimensional
result. The radio frequency spectrum of the system shows characteristic asymmetric dissociation
peak structure and a clear pairing gap emerges with increasing lattice depth as seen in experiments.
∗ Electronic address: sudeep@physics.iisc.ernet.in
† Electronic address: shenoy@physics.iisc.ernet.in