Effect of Pressure on the Electronic Structure and Optical Properties of FeSe: A DFT+DMFT Study*

Superconductivity in the iron-chalcogenide superconductors is extremely sensitive to pressure; $T_c$ increases from 8 K to 37 K upon applying pressure[1]. In order to better understand the sensitivity of $T_c$ to pressure in FeSe we have performed fully self-consistent Density Functional Theory - Dynamical Mean Field Theory (DMFT) (DFT-DMFT) computations with a continuous quantum Monte Carlo impurity solver as a function of compression and temperature. Using analytic continuation, we have computed spectral functions, Fermi surfaces, and the optical properties for comparison with experiments. Our preliminary results, obtained at room temperature show a $\sim$ 43\% reduction of the dc conductivity upon increasing the pressure from 0 to 2.6 GPa.\\[4pt] [1] S. Medvedev {\it et al.} Nat. Mater. {\bf 8}, 630 (2009).