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物理学报. 2008, 57(4): 2368-2373.
doi: 10.7498/aps.57.2368.
自旋-Peierls化合物GeCuO3电子结构的第一性原理研究
- 收稿日期: 2007-08-02
- 修回日期: 2007-09-18
- 刊出日期: 2008-04-25
摘要: 采用平面波赝势方法对自旋-Peierls化合物GeCuO3的电子结构进行了第一性原理研究.计算结果表明：Cu2+的3d轨道自由度被冻结,未配对电子填充dx2-y2轨道.自旋向上和向下的dx2-y2轨道间的交换劈裂导致了体系的绝缘性.费米能级附近的Cu 3d态与O(2) 2p态存
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关键词:
- GeCuO3 /
- 自旋-Peierls相变 /
- 第一性原理计算 /
- 共价绝缘体
English Abstract
First-principles study on the electronic structures of spin-Peierls compound GeCuO3
- Received Date:
02 August 2007
- Accepted Date:
18 September 2007
- Published Online:
25 April 2008
Abstract: The electronic structures of spin-Peierls (SP) compound GeCuO3 have been studied by first-principles calculations with plane wave pseudo-potential method. The calculated results indicate that the 3d orbital degree of freedom for the Cu2+ has been frozen, and the unpaired electrons occupy the dx2-y2 orbits. The exchange splitting of the spin-up and spin-down dx2-y2 orbitals leads to the insulating nature of the system. GeCuO3 belongs to the category of covalent insulators, since there are very strong hybridizations between the Cu 3d and O(2) 2p states around the Fermi level. These strong covalent interactions lead to not only the deviation of the ideal spin moment of the Cu2+, but also the stabilization of the one-dimensional antiferromagnetic (AFM) ordering. We fit the spin exchange coupling constants within the Noodleman's broken symmetry methods through the calculated total energy for the various spin ordered states of GeCuO3. The calculated results indicate that the one-dimensional AFM interactions along the c axis are very strong in GeCuO3, which is the essential reason that brings on the SP transition at low temperature.
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