Nonlinear pressure dependence of the direct band gap in adamantine ordered-vacancy compounds

Journal Article · Fri Jan 01 00:00:00 EST 2010 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.81.195201· OSTI ID:982740

Manjon, F J ^[1]; Gomis, ^[1]; Rodriguez-Hernandez, P ^[2]; Perez-Gonzalez, E ^[2]; Munoz, A ^[2]; Errandonea, D. ^[3]; Ruiz-Fuertes, J ^[3]; Segura, A ^[3]; Fuentes-Cabrera, Miguel A ^[4]; Tiginyanu, IM ^[5]; Ursaki, VV ^[5]

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1. Polytechnic University of Valencia
2. University of La Laguna
3. Universidad de Valencia, Spain
4. ORNL
5. Academy of Sciences of Moldova, Moldova

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.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 982740
• Journal Information: Physical Review B, Vol. 81, Issue 19; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
BRILLOUIN ZONES
DEFECTS
PRESSURE DEPENDENCE
VACANCIES