Localized basis sets for unbound electrons in nanoelectronics

TL;DR

This paper demonstrates how localized basis sets, especially Gaussian functions, can effectively expand unbound electron wave functions over specific energy ranges, aiding in first-principles nanoelectronic simulations.

Contribution

It introduces a method to expand unbound electron wave functions using localized basis sets, focusing on Gaussian functions for first-principles nanoelectronics applications.

Findings

Gaussian basis sets can accurately represent unbound electron states.

The approach is applicable to modeling field emission and STM at large bias.

The method simplifies calculations of electron lifetimes in strong electric fields.

Abstract

It is shown how unbound electron wave functions can be expanded in a suitably chosen localized basis sets for any desired range of energies. In particular, we focus on the use of gaussian basis sets, commonly used in first-principles codes. The possible usefulness of these basis sets in a first-principles description of field emission or scanning tunneling microscopy at large bias is illustrated by studying a simpler related phenomenon: The lifetime of an electron in a H atom subjected to a strong electric field.