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首页> 外文期刊>RSC Advances >Electronic structure and lattice dynamics of Ba2CuTeO6 single crystals
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Electronic structure and lattice dynamics of Ba2CuTeO6 single crystals

机译：Ba2Cuteo6单晶的电子结构和晶格动力学

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The electronic structure and lattice dynamics of Ba _(2) CuTeO _(6) single crystals were investigated through spectroscopic ellipsometry and Raman scattering measurements. The room-temperature optical absorption spectrum of Ba _(2) CuTeO _(6) presented a direct optical band gap at approximately 1.04 eV and exhibited four bands at approximately 1.45, 3.43, 4.65, and 5.79 eV. The optical absorption band at 1.45 eV was attributed to on-site Cu ~(2+) d–d transition. The other bands were attributed to charge-transfer transitions between the O 2p and Cu 3d or Te 5p states. The room-temperature Raman scattering spectrum of Ba _(2) CuTeO _(6) exhibited 16 phonon modes at approximately 85, 97, 104, 119, 160, 194, 380, 396, 404, 409, 492, 568, 574, 606, 679, and 751 cm ~(?1) . When the temperature decreased to less than 287 K, which is the temperature at which structural phase transition occurs from the monoclinic phase to the triclinic phase, additional phonon modes appeared at approximately 124, 128, 152, and 601 cm ~(?1) . On further cooling to lower than 75 and 15 K, which are the temperatures at which short- and long-range antiferromagnetic phase transitions occur, respectively, the phonon modes at approximately 97, 104, 124, 128, 152, 160, 194, 380, 396, 409, 568, 574, 606, and 679 cm ~(?1) exhibited softening, which indicates a coupling between the magnetic and lattice degrees of freedom. The stretching vibration of CuO _(6) octahedra located at 679 cm ~(?1) had the largest spin–phonon coupling constant (1.67 mRy ? ~(?2) ).
机译：通过光谱椭圆形测定和拉曼散射测量研究了BA _（2）Cuto _（6）单晶的电子结构和晶格动力学。 Ba _（2）Cutio _（6）的室温光学吸收光谱呈现出大约1.04eV的直接光带隙，并在大约1.45,3.43,4.65和5.79eV中显示出四个带。 1.45eV的光学吸收带归因于现场Cu〜（2+）D-D转换。另一个频带归因于O 2P和Cu 3D或TE 5P状态之间的电荷转移转换。 BA _（2）Cuto _（6）的室温拉曼散射光谱在大约85,97,104,119,160,194,380,396,404,409,492,568,574， 606,679和751 cm〜（？1）。当温度降低至小于287k时，这是从单斜相发生到三级相发生的结构相转变的温度时，附加的声子模式出现在大约124,128,152和601cm〜（β1）处。进一步冷却至低于75和15 k，这是分别发生短和远程反铁磁相转变的温度，位于大约97,104,124,128,152,160,194,380的声子模式，396,409,568,574,606和679cm〜（？1）表现出软化，表示磁性和晶格自由度之间的耦合。 CuO _（6）八面体的拉伸振动位于679cm〜（Δ1）的八叠地段具有最大的旋转声子耦合常数（1.67米，〜（？2））。

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