First-principles study on the electronic structure and optical properties of Tl2Cd2(SO4)3 and Rb2Cd2(SO4)3

• 来源期刊: 中国物理B（英文版）
• 关键词: langbeinite electronic structure band gap optical properties
• 年，卷（期）: 2007,（12）
• 页码范围: 3798-3802
• 页数: 5页
• 语种: 英文

摘要

With the help of ab initio full-potential linearized augmented plane wave (FPLAPW) method, calculating the electronic structure and linear optical properties is carried out for XCd2(SO4)3 (X =Tl, Rb). The results show that Tl2Cd2(SO4)3 (TlCdS) has a larger band gap than Rb2Cd2(SO4)3 (RbCdS) and the energy bands for RbCdS are more dispersive than those of TlCdS. From their partial densities of states (PDOS), we have observed that the hybridization between S ionic 2p and O atomic 2p orbitals forms SO4 ionic groups. The remarkable difference between RbCdS and TlCdS is, however, the degree of hybridization between cation (Tl and Rb) and its surrounding oxygen atoms. In the view of quantum chemistry, the strong p-d hybridization indicates the existence of their cation ionic bonds (Cd-O,Rb-O, and Tl-O). The calculations of TlCdS and RbCdS show their optical properties to be less anisotropic. Their anisotropies in the optical properties mainly occur in a low photon energy region of 5-16 eV.