Evolution of Fermi Level State Density in Ultrathin Films Near the Two Dimensional Limit: Experiment and Theory

TL;DR

This study investigates how the electronic density of states at the Fermi level in ultrathin silver films changes as the film approaches a single atomic layer, combining experimental measurements with theoretical models.

Contribution

It provides new experimental data and theoretical analysis on the evolution of Fermi level density of states in ultrathin films near the two-dimensional limit.

Findings

DOS at Fermi level follows a (1 - γ/d) dependence with film thickness

Density functional theory shows mutual influence of substrate and film near the interface

Experimental and theoretical results agree on the DOS behavior in ultrathin films

Abstract

Electronic density of states (DOS) at Fermi level has been investigated in ultrathin Ag films grown on Si(111)-(7x7) down to the two dimensional limit of a single atomic layer. Measurement of DOS at Fermi level by scanning tunneling spectroscopy shows an approximate (1 - {\gamma}/d) dependence, where {\gamma} is a constant and d is the film thickness. The results are explained in the light of an analytical theory as well as our density functional theory (DFT) calculations. DFT results also show that in the proximity of the interface the DOS values of the film and the substrate are mutually affected by each other.