Ultra-sensitive pressure dependence of bandgap of rutile-GeO2 revealed by many body perturbation theory

Atanu Samanta, Manish Jain, Abhishek K. Singh

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Abstract

The reported values of bandgap of rutile GeO2 calculated by the standard density functional theory within local-density approximation (LDA)/generalized gradient approximation (GGA) show a wide variation (∼2 eV), whose origin remains unresolved. Here, we investigate the reasons for this variation by studying the electronic structure of rutile-GeO2 using many-body perturbation theory within the GW framework. The bandgap as well as valence bandwidth at Γ-point of rutile phase shows a strong dependence on volume change, which is independent of bandgap underestimation problem of LDA/GGA. This strong dependence originates from a change in hybridization among O-p and Ge-(s and p) orbitals. Furthermore, the parabolic nature of first conduction band along X-Γ-M direction changes towards a linear dispersion with volume expansion.

Original languageEnglish
Article number064703
JournalJournal of Chemical Physics
Volume143
Issue number6
DOIs
StatePublished - 14 Aug 2015
Externally publishedYes

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