Evolution of the potential-energy surface of amorphous silicon

TL;DR

This study investigates how the energy landscape of amorphous silicon evolves during relaxation, revealing independent distributions of activation barriers and energy changes, which helps explain experimental calorimetry data.

Contribution

It introduces a detailed analysis of the energy surface evolution in amorphous silicon using ART nouveau, highlighting the independence of activation and relaxation processes.

Findings

Barrier-height distribution depends only on relaxation level.

Reverse-barrier height distribution is independent of relaxation.

Energy distribution is a convolution of barrier and reverse-barrier distributions.

Abstract

The link between the energy surface of bulk systems and their dynamical properties is generally difficult to establish. Using the activation-relaxation technique (ART nouveau), we follow the change in the barrier distribution of a model of amorphous silicon as a function of the degree of relaxation. We find that while the barrier-height distribution, calculated from the initial minimum, is a unique function that depends only on the level of distribution, the reverse-barrier height distribution, calculated from the final state, is independent of the relaxation, following a different function. Moreover, the resulting gained or released energy distribution is a simple convolution of these two distributions indicating that the activation and relaxation parts of a the elementary relaxation mechanism are completely independent. This characterized energy landscape can be used to explain nano-calorimetry measurements.