The energy landscape of silicon systems and its description by force fields, tight binding schemes, density functional methods and Quantum Monte Carlo methods

TL;DR

This study compares the accuracy of various computational methods in describing the energy landscape of silicon systems, finding that DFT methods perform well while force fields are less reliable.

Contribution

The paper provides a comprehensive comparison of density functional, tight binding, force field, and Quantum Monte Carlo methods for silicon energy landscapes, highlighting DFT's accuracy and force fields' limitations.

Findings

DFT methods accurately describe transition states and energy landscapes.

Force fields often produce rugged landscapes with many false minima.

Quantum Monte Carlo results serve as reference standards.

Abstract

The accuracy of the energy landscape of silicon systems obtained from various density functional methods, a tight binding scheme and force fields is studied. Quantum Monte Carlo results serve as quasi exact reference values. In addition to the well known accuracy of DFT methods for geometric ground states and metastable configurations we find that DFT methods give a similar accuracy for transition states and thus a good overall description of the energy landscape. On the other hand, force fields give a very poor description of the landscape that are in most cases too rugged and contain many fake local minima and saddle points or ones that have the wrong height.