ZrTe5、HfTe5的单晶生长及输运性质研究
关键词 过渡金属五碲化物 低文半金属 反常输运性质 热电制冷
毕业论文设计说明书外文摘要
Title The study on the growth and transport properties of single crystals HfTe5 and ZrTe5
Abstract
The crystal growth of transition-metal pentatellurides HfTe5 and ZrTe5 has been performed and their transport properties have been measured as a function of temperature and applied magnetic field. Single crystals of HfTe5 and ZrTe5 were grown by means of chemical vapor phase transport reactions and several measurement methods including XRD, VSM and PPMS were used to make some analysis and characterization on the crystal structure and transport properties. The results showed that at zero magnetic field the transition-metal pentatellurides HfTe5 and ZrTe5 are such systems with many novel transport behaviors, which exhibit a peak in their resistivity as a function of temperature and a zero-crossing of thermoelectric power at the same temperature. The application of a transverse magnetic field to the current has a profound effect on the resistivity peak and absolute thermoelectric power in these materials. So to some extent it is possible to optimize the thermoelectric properties of HfTe5 and ZrTe5 with different applied magnetic field.
Keywords transition-metal pentatellurides low-dimensional semimetal
anomalous transport properties thermoelectric refrigeration
目 次
1 绪论 1
1.1 引言 1
1.2 电荷密度波（CDW）简介 2
1.3 过渡金属五碲化物HfTe5、ZrTe5的研究进展 4
1.3.1 HfTe5、ZrTe5的合成与晶体结构 4
1.3.2 HfTe5、ZrTe5的反常物理性质 6
1.3.3 HfTe5、ZrTe5的热电应用探索 11
1.4 本文的主要研究工作 15
2 HfTe5、ZrTe5的样品制备及结构表征 16
2.1 引言 16
2.2 实验细节 17
2.3 实验结果及讨论 17
3 HfTe5、ZrTe5单晶样品相关输运性质研究 22
3.1 电阻率测量 22
3.1.1 引言 22
3.1.2实验细节 22
3.1.3实验结果及讨论 24
3.2 磁化率测量 25
3.2.1 引言 25
3.2.2实验细节 26
3.2.3实验结果及讨论 26
3.3 热电势测量 27
3.3.1引言 27
3.3.2实验细节 28
3.3.3实验结果及讨论 29
3.4 本章小结 30
结 论 32
致 谢 33