Emergence of Novel Superconductivity Near the Boundary between Semiconductor and Semimetal

Abstract

The discovery of superconductivity and its novel mechanisms has attracted attention in condensed matter physics. In this article, we review our recent work on pressure-induced superconductivity at the semiconductor-semimetal boundary regions in Ta₂NiSe₅ and LaOPbBiS₃. Ta₂NiSe₅ is known as the promising candidate for excitonic insulator, and our high-pressure experiments have led to the discovery of superconductivity and a phase diagram covering the transition from the semiconducting to the semimetallic regime. We also report on the pressure-induced superconductivity in the bismuth chalcogenide semiconductor LaOPbBiS₃ in the vicinity of the localization threshold.