Metal-induced gap states in epitaxial organic-insulator/metal interfaces

TL;DR

This paper demonstrates both experimentally and theoretically that metal-induced gap states can exist at epitaxial organic insulator/metal interfaces, with implications for interface magnetism and electronic properties.

Contribution

It provides the first combined experimental and theoretical evidence of MIGS in epitaxial organic insulator/metal interfaces, and predicts interface magnetism with certain metal substrates.

Findings

MIGS observed in alkane/Cu(001) interfaces via NEXAFS.

Ab initio calculations support MIGS existence.

Potential for interface magnetism with Ni substrate.

Abstract

We have shown, both experimentally and theoretically, that the metal-induced gap states (MIGS) can exist in epitaxially grown organic insulator/metal interfaces. The experiment is done for alkane/Cu(001) with an element-selective near edge x-ray absorption fine structure (NEXAFS), which exhibits a pre-peak indicative of MIGS. An {\it ab initio} electronic structure calculation supports the existence of the MIGS. When the Cu substrate is replaced with Ni, an interface magnetism (spin-polarized organic crystal at the interface) is predicted to be possible with a carrier doping.