为了观察V2O3粉末由绝缘体态到金属态的相变过程，我们用太赫兹时域光谱仪（Terahertztime-domainspectroscopy，简称THz-TDS）技术对V2O3混合粉末样品在低温下进行测量．通过分析V2O3样品在太赫兹频段的幅值和相位信息，得到样品的折射率、介电常数等光学参数．我们用Maxwell-Gamett有效媒质理论（Effectiverne—diumtheory，简称EMT）联系Boltzmann函数来描述样品的介电特性．计算所得结果与实验吻合很好，进一步验证了在相变温度附近V2O3粉末中的金属域部分体积分数随温度升高而逐渐增加，导致了相变的发生．
In order to observe the metal-insulator transition inV2O3 powder, we measuredV2O3 powder sample by terahertz time-domain spectroscopy (THz-TDS) in the temperature range from 8 K to 220K. Through the analysis of the transmission and phase information of Vz Os sample in the terahertz band, we got the sample' s complex refractive index and complex dielectric constant. Maxwell-Garnett effective medium theory (EMT) together with Boltzmann function is employed to describe the dielectric properties of the sample. The calculated results agree with the measurement indicating a metal-insulator phase transition, in which the volume fraction of metallic domain gradually increases with the temperature around the transition temperature.
参考文献
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