CAN AN EXCITONIC INSULATOR UNDER PRESSURE TRANSFORM INTO A SUPERCONDUCTOR

The question whether an indirect-gap excitonic insulator can transform under pressure into a superconductor, as opposed to a semi-metal, has been investigated using a simplified model of the effective electron-electron interaction in the system. It has been shown that under certain conditions, when the ratio mh/me of the average hole and electron masses is very different from 1, there is a definite possibility of a superconducting transition. Within the model, the superconducting transition temperature T c as a function of the carrier density nc (which depends on pressure) and the ratio mh/mc has been calculated.