Semimetallic and charge-ordered α-(BEDT-TTF)2I3: On the role of disorder in dc transport and dielectric properties
Semimetallic and charge-ordered α-(BEDT-TTF)2I3: On the role of disorder in dc transport and dielectric properties
复制标题
半金属和电荷有序 α-(BEDT-TTF)2I3：论无序在直流输运和介电性能中的作用
DOI：
10.1103/physrevb.96.075141
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发表时间：
2017
影响因子：
3.7
通讯作者：
S. Tomic
中科院分区：
文献类型：
--
作者：
T. Ivek;M. Culo;M. Kuvezdic;B. Korin-Hamzic;E. Tutis;M. Basletic;B. Mihaljevic;E. Tafra;A. Löhle;M. Dressel;D. Schweitzer;S. Tomic
是有机导体间电荷排序的一个突出例子。在这项工作中，我们探讨了在环境压力下电荷有序相和半金属相内输运的细节。在高温半金属相中，电子和空穴的迁移率和浓度以这样一种方式共同作用，产生了几乎与温度无关的电导率和低霍尔效应。我们将这些现象解释为主要的袋间散射的结果，它使两种类型的载流子的迁移率相等。在低温下，在绝缘电荷有序相内，可以识别两个传导通道：一个依赖于温度的激活，它遵循平均场行为，以及一个最近邻跳变贡献。与负磁阻一起，后者依赖于无序的存在。电荷有序相也具有与弛豫铁电体相似的突出的介电峰。它的色散是由自由电子筛选决定的，并由无序推动远低于转变温度。这种混乱的来源可以在阴离子层中找到，阴离子层通过氢键随机扰乱BEDT-TTF分子。
is a prominent example of charge ordering among organic conductors. In this work, we explore the details of transport within the charge-ordered as well as semimetallic phase at ambient pressure. In the high-temperature semimetallic phase, the mobilities and concentrations of both electrons and holes conspire in such a way to create an almost temperature-independent conductivity as well as a low Hall effect. We explain these phenomena as a consequence of a predominantly interpocket scattering which equalizes mobilities of the two types of charge carriers. At low temperatures, within the insulating charge-ordered phase two channels of conduction can be discerned: a temperature-dependent activation, which follows the mean-field behavior, and a nearest-neighbor-hopping contribution. Together with negative magnetoresistance, the latter relies on the presence of disorder. The charge-ordered phase also features a prominent dielectric peak which bears a similarity to relaxor ferroelectrics. Its dispersion is determined by free-electron screening and pushed by disorder well below the transition temperature. The source of this disorder can be found in the anion layers which randomly perturb BEDT-TTF molecules through hydrogen bonds.
影响因子：
6.8
作者：
S. Kluge
通讯作者：
S. Kluge