Electronic structure and bonding in garnet crystals Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12}, Gd{sub 3}Sc{sub 2}Al{sub 3}O{sub 12}, and Gd{sub 3}Ga{sub 3}O{sub 12} compared to Y{sub 3}Al{sub 3}O{sub 12}
- Department of Physics, University of Missouri-Kansas City, Kansas City, Missouri 64110 (United States)
- Allied Signal FM and T, Kansas City, Missouri 64141 (United States)
The electronic structure and bonding of Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12} (GSGG), Gd{sub 3}Sc{sub 2}Al{sub 3}O{sub 12} (GSAG), and Gd{sub 3}Ga{sub 5}O{sub 12} (GGG) crystals with a garnet structure are studied by means of first-principles local-density calculations. The results are compared with a similar calculation on yttrium aluminum garnet [Y{sub 3}Al{sub 5}O{sub 12} (YAG)]. The calculated equilibrium volumes of the three crystals are close to the measured volumes with a slight overestimation for GGG. GGG also has a smaller bulk modulus than the other three crystals. The calculated density of states and their atomic and orbital decompositions are presented and contrasted. All four crystals show very similar band structures and interatomic bonding. However, it is found that in GSGG and GSAG crystals, the Sc atom at the octahedral site shows a higher covalent character and an increased bond order in comparison to Ga or Al at the same site. This result may provide some insight into the significant difference in the radiation hardness of Cr{sup 3+}:Nd{sup 3+}:GSGG as compared to Nd{sup 3+}:YAG. (c) 2000 The American Physical Society.
- OSTI ID:
- 20215216
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 61, Issue 3; Other Information: PBD: 15 Jan 2000; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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