Superconductivity near ferroelectric quantum critical point in SrTiO3
일 시 : 2021년 11월 18일 목요일 16:00
연 사 : 정 석 범 교수 (서울시립대학교 물리학과)
장 소 : 온라인 진행 ( https://us02web.zoom.us/j/81101834598?pwd=RkZIdXJLL1lOWXBjamc2Ylg3VUtRZz09 )
HOST : 신 상 진 교수님
초 록
SrTiO3 has been long known as a quantum paraelectric due to its proximity to a lattice quantum criticality associated with inversion symmetry breaking. It has also been known to possess a superconducting ground state within a finite range of electron doping. Recent experiments on Nb-doped SrTiO3 have shown that the superconducting energy gap to the transition temperature ratio maintains the Bardeen-Cooper-Schrieffer (BCS) value throughout its superconducting dome. Motivated by these and related studies, I will show that the Cooper pairing mediated by a single soft transverse-optical phonon is the most natural mechanism for such a superconducting dome given experimental constraints, and present the microscopic theory for this pairing mechanism. Furthermore, we discuss what physical insights SrTiO3 provides for superconductivity in other quantum paraelectrics such as KTaO3.