Electrodynamics of the spin-density-wave ground state: Optical experiments on (TMTSF)2PF6.
Electrodynamics of the spin-density-wave ground state: Optical experiments on (TMTSF)2PF6.
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自旋密度波基态的电动力学：(TMTSF)2PF6 的光学实验。
DOI：
10.1103/physrevb.49.3363
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Wonneberger
中科院分区：
文献类型：
--
作者：
Donovan;Kim;Degiorgi;Dressel;Grüner;Wonneberger
报道了有机直链化合物(TMTSF${)}_{2}${MATHROM{Pf}}_{6}$在金属态和自旋密度波态下的电导测量结果。通过在射频、微波和毫米波以及红外光谱范围内的测量，确定了复合电导率的组成。在高于自旋密度波转变的温度下，发现了类似Drude的金属行为，并在较高的频率下具有与温度无关的特征。观测到的德鲁德散射率为3${mathm{cm}}^{\mathm{-}}1}$，将材料很好地置于清洁极限内。在自旋密度波状态下，低场直流电阻率表现出与标准半导体相似的激活行为，禁带宽度为2\ensuremath{\Delta}/${\mathit{k}}_{\mathit{B}}$\ensuremath{\approxeq}45 K。交流响应表现出很强的频率依赖性，最重要的是，我们观察到了两个亚能隙模式：由于自旋密度波的内部变形，在射频范围内有一个很宽的模式，而在0.1${mathm{cm}}^{\mathm{-}}1}$，我们将其解释为Q=0相激子的响应。此外，正如预期的那样，对于清洁极限的材料，我们在红外光谱范围内看不到单一粒子间隙的证据。在本文中，我们将把我们的实验结果与自旋密度波动力学的各种模型进行比较，并对目前对自旋密度波动力学响应的理解现状进行评论。
Conductivity measurements are reported in the organic linear-chain compound (TMTSF${)}_{2}$${\mathrm{PF}}_{6}$, in both the metallic and spin-density-wave states. The components of the complex conductivity were established by measurements in the radio-frequency, micro- and millimeter wave, and infrared spectral ranges. At temperatures above the spin-density-wave transition, a Drude-like metallic behavior was found together with a temperature-independent feature at higher frequencies. An observed Drude scattering rate of 3 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ was found, placing the material well into the clean limit. In the spin-density-wave state, the low-field dc resistivity shows an activated behavior similar to a standard semiconductor with a gap value 2\ensuremath{\Delta}/${\mathit{k}}_{\mathit{B}}$\ensuremath{\approxeq}45 K. The ac response shows a strong frequency dependence, and most importantly, we observe two subgap modes: a very broad one in the radio frequency range, due to internal deformations of the spin density wave, and a narrow mode near 0.1 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$, which we interpret as the response of the q=0 phason. Furthermore, as expected for a material in the clean limit, we do not see evidence for a single particle gap in the infrared spectral range. In this paper, we will compare our experimental results with the various models of spin-density-wave dynamics and comment on the current status of the understanding of the dynamical response of spin density waves.