6533b7d2fe1ef96bd125df2d
RESEARCH PRODUCT
Nonlinear pressure dependence of the direct band gap in adamantine ordered-vacancy compounds
Francisco Javier ManjónV. V. UrsakiMiguel Fuentes-cabreraIon TiginyanuJavier Ruiz-fuertesAlfonso MuñozDaniel ErrandoneaAlfredo SeguraE. Pérez-gonzálezOscar GomisPlácida Rodríguez-hernándezsubject
Brillouin zoneMaterials scienceAbsorption edgeCondensed matter physicsAb initio quantum chemistry methodsVacancy defectDirect and indirect band gapsAbsorption (logic)Crystal structureCondensed Matter PhysicsEnergy (signal processing)Electronic Optical and Magnetic Materialsdescription
A strong nonlinear pressure dependence of the optical absorption edge has been measured in defect chalcopyrites CdGa{sub 2}Se{sub 4} and HgGa{sub 2}Se{sub 4}. The behavior is due to the nonlinear pressure dependence of the direct band-gap energy in these compounds as confirmed by ab initio calculations. Our calculations for CdGa{sub 2}Se{sub 4}, HgGa{sub 2}Se{sub 4} and monoclinic {beta}-Ga{sub 2}Se{sub 3} provide evidence that the nonlinear pressure dependence of the direct band-gap energy is a general feature of adamantine ordered-vacancy compounds irrespective of their composition and crystalline structure. The nonlinear behavior is due to a conduction band anticrossing at the {Gamma} point of the Brillouin zone caused by the presence of ordered vacancies in the unit cell of these tetrahedrally coordinated compounds.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-05-04 | Physical Review B |