ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The origin of second harmonic generation (SHG) of Li3VO4 was investigated from the viewpoint of the band structure by using the tight-binding method. The tight-binding parameters were optimized to reproduce the density of states (DOS) obtained from x ray photoelectron spectroscopy and the optical band gap. Although Li3PO4 has the same crystal structure as Li3VO4, it shows no SHG. To explain the difference in optical nonlinearity we compared the electronic structures of Li3VO4 and Li3PO4, in particular at the bottom of conduction band (CB) and the top of valence band (VB), since they are known to play a primary role in SHG. In Li3PO4, the bottom of CB consists of P 3s and O 2p orbitals and the top of VB is composed of O 2p orbitals. These electronic structures result in a relatively low DOS at the bottom of CB and a wide band gap in Li3PO4. On the other hand, in Li3VO4, both bottom of CB and top of VB are composed of V 3d and O 2p. The preferential contribution of V 3d orbitals to the band edge states leads to a high DOS at the bottom of CB, a narrow band gap and delocalization of electrons on V–O bonds. We conclude that these electronic structures are responsible for the high optical-nonlinearity of Li3VO4. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.363314
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