High-temperature superconductivity and quantum Griffith singularity in two-dimensional crystal

Abstract

Superconductors have become one of the most important directions in condensed matter physics and materials science due to their unique properties incuding zero-resistance and perfect diamagnetism. With the development of the fabrication technique of two-dimensional (2D) single crystals, 2D superconductors have recently come to be a new research frontier, in which novel physics phenomena, such as high-temperature superconductivity and quantum phase transitions, have emerged and received wide attention. In this artcle, we first briefly review the research background and basic properties of 2D superconductors. Then, focusing on two important classes of phenomena—high-temperature superconductivity and quantum phase transitions, the article is organized into two parts. In the first part, we introduce a typical example of high-temperature superconductivity in 2D systems, the ultrathin FeSe films grown on SrTiO3 (STO) substrate, including the experimental properties and mechanism discussions. In the second part, as an example of quantum phase transitions in 2D systems, an overview of the theories and experiments of the newly-discovered quantum Griffiths singularity in 2D crystalline superconductors is given. In the end, we summary the high-temperature superconductivity and quantum Griffiths singularity in 2D crystals and provide an outlook of the future development in the relevant frontiers.