Atomic-layer Superconductivity Modified by Adsorption of Organic Molecules

Abstract

The superconducting properties of atomic layers are strongly affected by the presence of surfaces and interfaces. In this study, we aim to elucidate the mechanism by which the superconducting transition temperature T_c is modulated by the adsorption of organic molecules. We have performed a comprehensive study on the atomic layer superconductor Si(111)-(√7×√3)-In with adsorption of ZnPc molecules using electron transport measurements, angle-resolved photoemission spectroscopy, and ab initio calculations. Through comparison with previous studies, the results show that the observed T_c increase cannot be attributed to the charge transfer from molecules as previously thought. We propose a new mechanism based on the push-back effect caused by molecule adsorption.