Metal-insulator crossover in FeSb2 within LQSGW+DMFT

Although the thermoelectric properties of FeSb$_2$ are attracting attention due to its colossal thermopower and record-high thermoelectric power factor, the diamagnetic insulator-paramagnetic metal crossover does not fit within one-particle picture and are the subject of active research. Several theoretical models have been proposed to go beyond one-particle picture. However unified theory incorporating local and non-local electronic correlation and hybridization between the correlated and itinerant bands on the same footing is still missing. In this talk, we will discuss the effect of the electronic correlation and the hybridization to the crossover in FeSb$_2$. By using fully \textit{first-principles} approaches of LQSGW+DMFT without any adjustable parameters, we will show temperature evolution of spectral function, optical conductivity and local spin- and charge-fluctuation and make a comparison with experiments.