Local Lattice Distortion Around V Pb 2 in PbWO 4 and the Origin of the 420 nm Luminescence Band
2004; Institute of Physics; Volume: 21; Issue: 8 Linguagem: Inglês
10.1088/0256-307x/21/8/052
ISSN1741-3540
AutoresLiu Ting‐Yu, Qiren Zhang, Zhenqing Li,
Tópico(s)Gas Sensing Nanomaterials and Sensors
ResumoThe lattice structures around one lead vacancy VPb2− in PbWO4 are studied within the framework of the full-relativistic density functional theory. Using the conjugate gradient method, we optimize the geometry of the ions around VPb2− by moving the ions within the sub-cell until specified tolerance is satisfied. We obtain the geometric positions of ions around VPb2− after optimization. The calculated results indicate that there would be local lattice distortion caused by the existence of VPb2−. The electronic structures of both the optimized and pre-optimized PWO containing VPb2− have been calculated. The density of states of the distorted PWO indicates that the energy gap between the 2p state of O2− and the 5d state of W6+ is 3.90 eV, which shows that the distorted W–O tetrahedron may be the 420 nm luminescence centre.
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