Electronic band structure of zirconia and hafnia polymorphs from the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>G</mml:mi><mml:mi>W</mml:mi></mml:mrow></mml:math>perspective
Physical review. B, Condensed matter and materials physics