Second harmonic generation in SiC polytypes

TL;DR

This paper presents theoretical calculations of second harmonic generation in various SiC polytypes, analyzing spectral features and tensor components to understand their optical properties and band structure relationships.

Contribution

It provides detailed LMTO calculations of SHG tensor components across multiple SiC polytypes, linking spectral features to structural and electronic properties.

Findings

SHG tensor components vary with polytype

Spectral features relate to band edge excitations

SHG can probe interband transitions near the band edge

Abstract

LMTO calculations are presented for the frequency dependent second harmonic generation (SHG) in the polytypes 2H, 4H, 6H, 15R and 3C of SiC. All independent tensor components are calculated. The spectral features and the ratios of the 333 to 311 tensorial components are studied as a function of the degree of hexagonality. The relationship to the linear optical response and the underlying band structure are investigated. SHG is suggested to be a sensitive tool for investigating the near band edge interband excitations.