Unconventional quantum fluid at high magnetic fields in the marginal charge-density-wave systemα−(BEDT−TTF)2MHg(SCN)4(M=Kand Rb)
Unconventional quantum fluid at high magnetic fields in the marginal charge-density-wave systemα−(BEDT−TTF)2MHg(SCN)4(M=Kand Rb)
复制标题
边缘电荷密度波系统中高磁场下的非常规量子流体α−(BEDT−TTF)2MHg(SCN)4(M=Kand Rb)
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
L. Montgomery
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文献类型：
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作者：
N. Harrison;J. Singleton;A. Bangura;A. Ardavan;P. Goddard;R. McDonald;L. Montgomery
用霍尔电势测量(M=K)和磁化实验(M=K，Rb)研究了有机电荷转移盐α-(BEDT-TTf)_2-MHg(SCN)_4单晶。数据表明，在这些盐的强磁场、低温电荷密度波(CDWx)相中，随着磁场的变化，出现了两种屏蔽电流。第一个产生感生霍尔势的是存在于样品表面的自由电流(J F R E E)。这些电流衰减的时间常数比样品电阻率的预期时间常数要长得多。电流的第二个分量似乎是磁性的(J M A G)，因为它是一种微观的准轨道效应；当饱和时，它均匀地分布在样品中。为了解释这些数据，我们提出了一个简单的模型，该模型调用了一种新型的量子流体，它包括一个共存的CDW和一个描述这两种电流的二维费米面口袋。该模型和数据能够解释之前的实验数据，这些数据在量子霍尔效应或超导电性方面产生了明显相互矛盾的解释。
Single crystals of the organic charge-transfer salts α-(BEDT-TTF) 2 M Hg(SCN) 4 have been studied using Hall-potential measurements (M=K) and magnetization experiments (M=K, Rb). The data show that two types of screening currents occur within the high-magnetic-field, low-temperature charge-density wave (CDW x ) phases of these salts in response to time-dependent magnetic fields. The first, which gives rise to the induced Hall potential, is a free current (j f r e e ), present at the surface of the sample. The time constant for the decay of these currents is much longer than that expected from the sample resistivity. The second component of the current appears to be magnetic (j m a g ), in that it is a microscopic, quasiorbital effect; it is evenly distributed within the bulk of the sample upon saturation. To explain these data, we propose a simple model invoking a new type of quantum fluid comprising a CDW coexisting with a two-dimensional Fermi-surface pocket which describes the two types of current. The model and data are able to account for the body of previous experimental data which had generated apparently contradictory interpretations in terms of the quantum Hall effect or superconductivity.