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Thermoelectric effect of quasicrystals and development of thermoelectric-device materials by controlling the psuedogap

准晶的热电效应及通过控制赝能隙开发热电器件材料

基本信息

批准号：
10554016
负责人：
MIZUTANI Uichiro
金额：
$ 8.58万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10554016/
关键词：
quasicrystal approximant pseudogap thermoelectric power Seebeck coefficient Mott theory 熱電材料熱電素子

项目摘要

The presence of the pseudogap across the Fermi level has been regarded as one of the most characteristic features in quasicrystals and their approximates and is known to affect critically the electron transport properties. The concept of the pseudogap has been established by Mott in 1968 in his discussion of the metal-insulator transition of liquid mercury at high temperatures and high pressures. The principal investigator demonstrated the validity of the Mott theory for quasicrystals and their approximants by showing that the electrical conductivity is proportional to the square of the depth of the pseudogap and provided firm basis for the research aiming at the application of unique transport properties of quasicrystals and their approximants.In the present project, we focused on the thermoelectric effect. The thermoelectric device is the device, which is capable of transforming heat into electricity or electricity into heat. The latter is expected to be applicable to the electronic refrigerator. We have measured the thermoelectric power in the temperature range 80-400 K and aimed at establishing the guiding principles to develop the thermoelectric device materials in the family of quasicrystals and apploximants.In the year of Heisei 10, we purchased the thermoelectric power acquisition system by using this fund and could successfully test the machine by measuring the Seebeck coefficient of Al-Mg-Pd and Al-Mg-Zn quasicrystals.In the year of Heisei 11, we extended the measurements to Al-Cu-Fe, Al-Cu-Fe-Si and Al-Pd-Mn systems. We revealed that both Seebeck coefficient and Hall coefficient concomitantly change the sign from a positive to negative one by varying Fe concentration in the Al-Cu-Fe system. We concluded from this that the system changes from the electron to hole states. We also revealed that the single quasicrystal Al-Mn-Pd exhibits the Seebeck coefficient of 80 μV/K, which is almost independent of the orientation of the quasicrystal.

费米能级上赝能隙的存在被认为是准晶体及其近似晶体中最具特征的特征之一，并且已知对电子传输特性有重要影响。赝能隙的概念是莫特于 1968 年在讨论高温高压下液态汞的金属-绝缘体转变时提出的。主要研究者通过电导率与赝能隙深度的平方成正比，证明了准晶及其近似材料莫特理论的有效性，为准晶及其近似材料独特输运性质的应用研究提供了坚实的基础。在本项目中，我们主要研究热电效应。热电装置是能够将热能转化为电能或将电能转化为热能的装置。后者有望适用于电子冰箱。我们测量了80-400 K温度范围内的热电势，旨在建立开发准晶和近似晶族热电器件材料的指导原则。平成10年，我们利用这笔资金购买了热电势采集系统，并通过测量Al-Mg-Pd和Al-Mg-Zn的塞贝克系数成功测试了机器平成11年，我们将测量扩展到Al-Cu-Fe、Al-Cu-Fe-Si和Al-Pd-Mn系。我们发现，通过改变 Al-Cu-Fe 体系中的 Fe 浓度，塞贝克系数和霍尔系数都会同时将符号从正变为负。我们由此得出结论，系统从电子态转变为空穴态。我们还发现，单个准晶 Al-Mn-Pd 的塞贝克系数为 80 μV/K，这几乎与准晶的取向无关。