V_2O_3粉末金属-绝缘体相变的太赫兹光谱分析  

METAL-INSULATOR TRANSITION IN V_2O_3 POWDER MEASURED BY TERAHERTZ TIME-DOMAIN SPECTROSCOPY

作　　者：唐伟捷[1] 顾翔[1] 吴敬波[1] 金飚兵[1] 

机构地区：[1]南京大学超导电子学研究所,江苏南京210093

出　　处：《低温物理学报》2012年第6期413-416,共4页Low Temperature Physical Letters

基　　金：国家973项目(批准号:2011CBA00107);国家自然科学基金(批准号:61071009和61027008);教育部博士点基金(批准号:20090091110040)资助的课题~~

摘　　要：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(Terahertz time-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-Garnett有效媒质理论(Effective me-dium theory,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.

关 键 词：V2O3相变 太赫兹时域光谱技术 太赫兹光学参数 有效媒质理论 

分 类 号：TN211[电子电信—物理电子学]