Magnetotransport and Fermi-surface topology of beta "-(BEDT-TTF)2AuBr2: The effects of spin-density-wave formation.
Magnetotransport and Fermi-surface topology of beta "-(BEDT-TTF)2AuBr2: The effects of spin-density-wave formation.
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β“-(BEDT-TTF)2AuBr2 的磁输运和费米表面拓扑：自旋密度波形成的影响。
DOI：
10.1103/physrevb.49.3934
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Day
中科院分区：
文献类型：
--
作者：
Doporto;Singleton;Pratt;Caulfield;Hayes;Perenboom;Deckers;Pitsi;Kurmoo;Day
在高达50T的磁场下，对金属电荷转移盐β‘-(BEDT-TTf)2AuBr2的一些单晶样品进行了磁阻测量，测量了样品相对于磁场的大范围取向和80mK到4.2K的温度范围。磁阻表现出一系列复杂的Shubnikov-de Haas振荡，各向异性角依赖，以及在1K以下的磁滞。在Shubnikov-de Haas谱中观察到的磁阻滞后效应和混频效应都可以用Shoenberg磁相互作用效应来解释，并且这一机制已成功地用于模拟观测到的磁阻的傅里叶谱。提出了β‘-(BEDT-TTF)2AuBr2的复数Shubnikov-de Haas频谱是由于自旋密度波对能带结构的影响，改变了原来的费米面，形成了三个二维载流子口袋。利用Shubnikov-de Haas振荡幅度与角度的依赖关系，推导出了这些口袋的近似形状和取向，与所提出的模型定性地吻合得很好。
Magnetoresistance measurements have been made on a number of single-crystal samples of the metallic charge-transfer salt beta''-(BEDT-TTF)2AuBr2, using magnetic fields up to 50 T. The experiments have been carried out for a wide range of orientations of the sample with respect to the magnetic field and for temperatures ranging between 80 mK and 4.2 K. The magnetoresistance exhibits a complex series of Shubnikov-de Haas oscillations, an anisotropic angle dependence, and, below 1 K, hysteresis. Both the hysteresis in the magnetoresistance and frequency mixing effects observed in the Shubnikov-de Haas spectrum can be explained by the effects of Shoenberg magnetic interaction, and this mechanism has been successfully used to model the observed Fourier spectrum of the magnetoresistance. The complex Shubnikov-de Haas frequency spectrum of beta''-(BEDT-TTF)2AuBr2 is proposed to result from the effects of a spin-density wave on the band structure, which alters the original Fermi surface to produce three two-dimensional carrier pockets. The angle dependence of the Shubnikov-de Haas oscillation amplitudes has been used to deduce the approximate shapes and orientations of these pockets, which are found to be in good qualitative agreement with the proposed model.