Dynamics of electrical conductions for the materials confined in continuous nano-space

在介孔碳CMK体系中，存在着各种各样的结构。我们对这些CMK体系的电导率和磁化率进行了测量。因此，我们澄清了低温导电性质是由二维可变范围跳跃机制引起的。在零场冷却下，磁化率在60K附近出现最大值，而在场冷却下，磁化率仅表现出增加的趋势。这些事实表明，在这些介孔碳系统中形成了自旋玻璃态。我们预计自旋来自组成介孔结构的石墨片中的非键π电子。为了检测低维电子系统的动力学性质，我们实现了在太赫兹频率范围内的光谱测量。我们采用了基于时域光谱的透射率测量方法。复电导率和复介电常数随频率的变化范围为0.1~2 THz。由于我们对低温动力学有很大的兴趣，我们在太赫兹装置中安装了光学低温恒温器。利用太赫兹光谱仪测量了Nb膜、自组织DNA膜和各种介孔体系的高频动力学特性，并测量了人工合成的干DNA晶体的微波电导率和红外光谱。我们已经发现了初级水合作用的重要性，即使在干燥的DNA系统中也是如此。

In the mesoporous carbon CMK systems, there exist a wide variety of structures. We have carried out the measurements on the electrical conductivities and magnetic susceptibilities in these CMK systems. As a result, we have clarified that low-temperature conducting properties are caused by a two-dimensional variable range hopping mechanism. Under zero-field cooling, the magnetic susceptibility takes a maximum in the vicinity of 60K though, under field cooling, the susceptibilities only exhibit an increase. These facts indicate a formation of spin-glass states in these mesoporous carbon systems. We expect that the spin originates from non-bonding π-electrons in graphen sheets composing the mesoporous structure.In order to detect dynamical properties of low-dimensional electronic systems, we have realized spectroscopic measurement in the range of terahertz frequency. We employ the transmission measurement based on time-domain spectroscopy. The frequency dependence of complex conductivity and complex dielectric constant are determined from 0.1 to 2 THz. Since we have much interests in the low temperature dynamics, the optical cryostat has been installed in the terahertz unit. Now the minimum measuring temperature is achieved to be 2 K. With use of the terahertz spectrometer, we have measured niobium films, self-organizing DNA films and various mesoporous systems to obtain high-frequency dynamics.In addition, the microwave conductivity and infrared spectra were measured for artificially synthesized dry DNA crystals. We have found the importance of the role of primary hydration even in the dry DNA systems.