Effect of Dielectric Confinement on Energetics of Quantum Metal Films: Analysis of Calculation Results

Abstract

We examine thin film on a dielectric substrate (vacuum/Al/SiO2) in the stabilized jelly model. We investigate the surface and size effects on the effective potential and the electron work function for the weak quantization regime. We find that a dielectric environment generally leads to the decrease of the work function. We introduce the position of a conduction band for the dielectric as the input parameter in the self-consistency procedure. The effect of dielectric confinement for the energy characteristics of the asymmetric metal-dielectric sandwiches is reduced to only by the surface-area weighted average value of the dielectric constants. This conclusion follows from the application of the Gauss theorem for a conducting sphere with an inhomogeneous dielectric coating. The flow of electrons from the dielectric face to the vacuum one due to the contact-potential difference manifests itself in the appearance of a potential barrier above the vacuum level or positive values of the effective potential. The barrier height depends on the used local or nonlocal approximation of the exchange-correlation energy. The nontrivial origin and behaviour of the calculated effective potential on the vacuum side of the film, as well as the reasons for it, are discussed. In the focus of our representations, we analyse the recent results of measurements of the contactpotential difference depending on the number of Si atoms deposited on the free face of ytterbium nanofilms on the Si(111) substrates. Comparison and discrepancies between our self-consistent calculations for simple metals and these experiments are discussed.

The Influence of the Components of the 06ХН28МДТ Alloy (Analogue of AISI904L Steel) and the Parameters of the Model Chloride-Containing Recycled Water of Enterprises on Its Pitting Resistance

“…It is known that in the statistical description of a metal drop, the pressure tensor, including T = 0 K, contains the Maxwell stress tensor, which depends on the dielectric constant of the environment [20,41,42]. Recent works [41][42][43] have developed an approach to the problem of a metal surface with a non-uniform dielectric coating. Attention is drawn to the fact that the work function of the metal depends on the dielectric constant ε  weighted average over the contact area.…”

“…If a metal droplet of area S is in the vapour phase with a constant ε v , but touches a dielectric substrate with a constant ε (contact area αS, α < 1), then the effective influence of the substrate and vapour, as follows from the Gauss theorem [43], is reduced to calculating the work function of the droplet in a homogeneous fictitious dielectric medium with constant…”