Transition from Mott insulator to superconductor in GaNb${}_4$Se${}_8$ and GaTa${}_4$Se${}_8$ under high pressure

M. M. Abd-Elmeguid, B. Ni, D. I. Khomskii +4

Electronic conduction in GaM${}_4$Se${}_8$ (M=Nb;Ta) compounds with the fcc GaMo${}_4$S${}_8$-type structure originates from hopping of localized unpaired electrons (S=1/2) among w…