The use of experimental data in constraining the tight-binding band parameters of quasi-two-dimensional organic molecular metals: application to alpha-(BEDT-TTF)2KHg(SCN)4
The use of experimental data in constraining the tight-binding band parameters of quasi-two-dimensional organic molecular metals: application to alpha-(BEDT-TTF)2KHg(SCN)4
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实验数据在约束准二维有机分子金属紧束缚带参数中的应用：应用于α-(BEDT-TTF)2KHg(SCN)4
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
M. Kurmoo
中科院分区：
文献类型：
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作者：
N. Harrison;E. Rzepniewski;J. Singleton;P. Gee;M. Honold;P. Day;M. Kurmoo
虽然紧束缚能带结构的计算是非常成功的描述费米面配置在许多准二维有机分子金属，预测的费米面的详细拓扑结构往往不同于在实验中测量。这是非常重要的，例如，密度波态的形成关键取决于费米面片嵌套的细节。这些理论和实验之间的差异可能是由于有限的准确性，其中的-轨道的组件分子（这引起了紧束缚能带结构的转移积分）是已知的。为了克服这个问题，我们已经推导出一种方法，其中紧束缚能带结构模型内的转移积分进行调整，直到详细的费米面拓扑结构是在很好的协议与各种各样的实验数据。该方法被应用到电荷转移盐-（BEDT-TTF）2KHg（SCN）4，费米面的来源，近年来一直是许多猜测。得到的费米面在细节上不同于以前的能带结构计算结果。特别是，费米面的准一维分量更强烈地翘曲。这意味着，在嵌套的这些片，准一维片的重要部分仍然存在，导致一个复杂的费米面拓扑结构内的低温，低磁场相。与以前的模型相比，在这项工作中重建的费米面模型可以解释几乎所有目前的实验观察一致的方式。
Whilst tight-binding bandstructure calculations are very successful in describing the Fermi-surface configuration in many quasi-two-dimensional organic molecular metals, the detailed topology of the predicted Fermi surface often differs from that measured in experiments. This is very significant when, for example, the formation of a density-wave state depends critically on details of the nesting of Fermi-surface sheets. These differences between theory and experiment probably result from the limited accuracy to which the -orbitals of the component molecules (which give rise to the transfer integrals of the tight-binding bandstructure) are known. In order to surmount this problem, we have derived a method whereby the transfer integrals within a tight-binding bandstructure model are adjusted until the detailed Fermi-surface topology is in good agreement with a wide variety of experimental data. The method is applied to the charge-transfer salt -(BEDT-TTF)2KHg(SCN)4, the Fermi surface of which has been the source of much speculation in recent years. The Fermi surface obtained differs in detail from previous bandstructure calculation findings. In particular, the quasi-one-dimensional component of the Fermi surface is more strongly warped. This implies that upon nesting of these sheets, significant parts of the quasi-one-dimensional sheets remain, leading to a complicated Fermi-surface topology within the low-temperature, low-magnetic-field phase. In contrast to previous models of this phase, the model for the reconstructed Fermi surface in this work can explain virtually all of the current experimental observations in a consistent manner.