Effect of disorder on the charge-carrier dynamics in κ -(D8-ET)2Cu[N(CN)2]Br
Effect of disorder on the charge-carrier dynamics in κ -(D8-ET)2Cu[N(CN)2]Br
复制标题
无序对 κ -(D8-ET)2Cu[N(CN)2]Br 载流子动力学的影响
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
J. Schlueter
中科院分区：
文献类型：
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作者：
J. Brandenburg;J. Müller;J. Schlueter
本文应用电阻涨落谱研究了{kappa}-（D{sub 8}-ET）{sub 2}Cu[N（CN）{sub 2}]Br体系在两种不同冷却速率下的本征低频动力学行为。在热力学玻璃化转变温度T{sub g}以下观察到电阻和噪声水平的强烈增加。令人惊讶的是，除了Mott临界点（T{sub 0} {approx_equal} 35 K）附近和28 K以下的温度外，对于两种冷却速率，归一化光谱权重/R{sup 2}的数据都落在彼此的顶部。与Mott转变相关的/R{sup 2}中的峰的抑制表明，无序是广义相图中的附加参数。28 K以下的增强噪声水平可以解释由无序引起的交错磁矩在金属状态接近反铁磁莫特绝缘体。
We have applied resistance fluctuation spectroscopy to study the intrinsic low-frequency dynamics of the charge carriers in the system {kappa}-(D{sub 8}-ET){sub 2}Cu[N(CN){sub 2}]Br for two different cooling rates. A strong increase of both the resistance and the noise level is observed below the thermodynamic glass-transition temperature T{sub g}. Surprisingly, the data of the normalized spectral weight /R{sup 2} fall on top of each other for both cooling rates except for temperatures near the Mott critical point (T{sub 0} {approx_equal} 35 K) and below 28 K. The suppression of the peak in /R{sup 2} associated with the Mott transition suggests that disorder is an additional parameter in the generalized phase diagram. The enhanced noise level below 28 K might be explained by a disorder-induced staggered magnetic moment in the metallic state close to the antiferromagnetic Mott insulator.