Heterostructural one-unit-cell FeSe/SrTiO3: from high-temperature superconductivity to topological states

TL;DR

This paper reviews the significant enhancement of superconductivity and emergence of topological states in one-unit-cell FeSe/SrTiO3 heterostructures, highlighting their potential for next-generation quantum technologies.

Contribution

It provides a comprehensive overview of Tc enhancement, electron pairing mechanisms, and topological phases in ultrathin FeSe/SrTiO3, emphasizing their novel properties and technological potential.

Findings

Superconducting Tc approaches liquid nitrogen temperature.

Absence of hole pockets challenges conventional pairing theories.

Potential coexistence of high-Tc superconductivity and topological states.

Abstract

High temperature superconductivity in one unit cell (1 UC) FeSe on SrTiO3 heterostructure has become a research frontier in condensed matter physics and material science. The superconducting transition temperature (Tc) of ultrathin FeSe film is significantly enhanced compared to its bulk counterpart and possibly approaches the liquid nitrogen region according to in situ spectroscopic measurements. Particularly, the Fermi surface topology of 1 UC FeSe consists of no hole pockets at Brillouin zone center, which poses a great challenge to the well accepted s+- wave pairing nesting the sign different electron hole Fermi pockets in iron based superconductors. In this review, we present the explorations of Tc enhancement, electron pairing and topological phases in 1 UC FeSe on SrTiO3. The potential coexistence of high temperature superconductivity and topological electronic states promotes such two dimensional heterostructure as the candidate of next generation connate high temperature topological superconductor and (or) topological quantum computation platform.