Publication Date:
2015-08-14
Description:
The reported values of bandgap of rutile GeO 2 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-GeO 2 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.
Print ISSN:
0021-9606
Electronic ISSN:
1089-7690
Topics:
Chemistry and Pharmacology
,
Physics
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