Theoretical study of spherical kagome clusters in Mo72 V30 and W72 V30
Theoretical study of spherical kagome clusters in Mo72 V30 and W72 V30
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Mo72 V30和W72 V30球形戈薇团簇的理论研究
DOI：
10.1093/ptep/ptu036
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发表时间：
2014
影响因子：
3.5
通讯作者：
Nobutaka Kunisada and Yoshiyuki Fukumoto
中科院分区：
文献类型：
--
作者：
桜井 裕也;Kolodiazhnyi Taras;道上 勇一;室町 英治;田邊 雄一;菊池彦光;Nobutaka Kunisada and Yoshiyuki Fukumoto
用Lanczos方法分析了MoV和WV中的自旋1/2球形kagomé团簇，或量子自旋二十面体十二面体。磁化率分析表明，虽然MoV含有一定程度的结构扭曲，从而减小了其自旋能隙，但WV的结构可以描述为规则的(无扭曲的)二十硅十二面体。我们确定了四种类型的MoV交换参数，并阐明了引起自旋能隙抑制的扭曲机制。非扭曲的WV系统在第一三重态激发下有大约80个低位单重态。对两种材料的比热进行了计算和比较，以说明高能态数对WV低温比热的影响。为了确定如何通过拉曼散射实验观察到低激发态的单线态，对WV的拉曼光谱进行了数值计算。
Spin-1/2 spherical kagomé clusters, or quantum-spin icosidodecahedrons, occurring in MoVand WVare analyzed using the Lanczos method. Magnetic susceptibility analysis reveals that, whereas MoVcontains some degree of structural distortion that decreases its spin gap, the structure of WVcan be described as a regular (non-distorted) icosidodecahedron. We determine the four types of exchange parameter for MoVand clarify the mechanism of distortion that causes spin-gap suppression. The non-distorted WVsystem has about eighty low-lying singlet states below the first triplet excitation. The specific heats of the two materials are calculated and compared in order to illustrate the effects of high numbers of low-energy states on the low-temperature specific heat of WV. Numerical calculations of the Raman spectrum of WVare carried out in order to determine how the low-lying singlet states can be observed through Raman scattering experiments.