Conduction band tight-binding description for silicon applied to phosphorous donors

TL;DR

This paper presents a new tight-binding model for silicon that accurately captures conduction band properties and improves the description of phosphorus donor impurities compared to previous models.

Contribution

The paper introduces a silicon tight-binding parametrization optimized for effective masses and conduction band minima, enhancing donor impurity modeling accuracy.

Findings

The new parametrization accurately reproduces silicon's conduction band features.

Full band effects are crucial for reliable donor wavefunction representation.

Truncated reciprocal space expansions can lead to incomplete real space descriptions.

Abstract

A tight-binding parametrization for silicon, optimized to correctly reproduce effective masses as well as the reciprocal space positions of the conduction-band minima, is presented. The reliability of the proposed parametrization is assessed by performing systematic comparisons between the descriptions of donor impurities in Si using this parametrization and previously reported ones. The spectral decomposition of the donor wavefunction demonstrates the importance of incorporating full band effects for a reliable representation, and that an incomplete real space description results from a truncated reciprocal space expansion as proposed within the effective mass theory.