Growth, Electronic Structure and Superconductivity of Ultrathin Epitaxial CoSi2 Films

TL;DR

This study investigates ultrathin epitaxial CoSi2 films on Si(111), revealing quantum well states, electronic structure details, and persistent superconductivity down to 10 monolayers, with implications for microelectronics.

Contribution

It provides new insights into the growth, electronic structure, and superconductivity of ultrathin CoSi2 films, highlighting quantum confinement effects and superconducting properties at reduced thicknesses.

Findings

Quantum well states observed with dispersion matching DFT calculations

Superconductivity persists down to 10 monolayers with reduced Tc

Enhanced upper critical field in ultrathin films

Abstract

We report growth, electronic structure and superconductivity of ultrathin epitaxial CoSi2 films on Si(111). At low coverages, preferred islands with 2, 5 and 6 monolayers height develop, which agrees well with the surface energy calculation. We observe clear quantum well states as a result of electronic confinement and their dispersion agrees well with density functional theory calculations, indicating weak correlation effect despite strong contributions from Co 3d electrons. Ex-situ transport measurements show that superconductivity persists down to at least 10 monolayers, with reduced Tc but largely enhanced upper critical field. Our study opens up the opportunity to study the interplay between quantum confinement, interfacial symmetry breaking and superconductivity in an epitaxial silicide film, which is technologically relevant in microelectronics.