低激发密度下莫特绝缘体YTiO $_{3}$中局部光生载流子的太赫兹电导率,与带半导体Si中的金属性质形成对比
Terahertz conductivity of localized photoinduced carriers in Mott insulator YTiO$_{3}$ at low excitation density, contrasted with metallic nature in band semiconductor Si
摘要:
我们使用激光二极管(1.47 eV)和飞秒脉冲激光(1.55 eV)对莫特绝缘体YTiO $_{3}$和能带半导体Si进行了光泵太赫兹探针测量。这两种样品具有较长的能量弛豫时间(1.5 ms的YTiO $_{3}$和15 $μ$ s的Si),因此,它是可能的,以提取太赫兹复合电导率的光生载流子平衡。我们观察到高度对比的行为- Drude导电性在Si和局域导电性可能服从Jonscher法律在YTiO $_{3}$。YTiO $_{3}$中载流子浓度最高层的载流子数估计为0.015/Ti位。测定了YTiO $_{3}$的各向异性电导率。我们的研究表明,局域载流子可能在莫特绝缘体中光致金属相的早期形成中起重要作用。此外,本研究也显示出转移矩阵法对于空间不均匀载子分布的样品的光学常数的提取是有效的。
英文摘要:
We performed optical-pump terahertz-probe measurements of a Mott insulator YTiO$_{3}$ and a band semiconductor Si using a laser diode (1.47 eV) and a femtosecond pulse laser (1.55 eV). Both samples possess long energy-relaxation times (1.5 ms for YTiO$_{3}$ and 15 $μ$s for Si); therefore, it is possible to extract terahertz complex conductivities of photoinduced carriers under equilibrium. We observed highly contrasting behavior - Drude conductivity in Si and localized conductivity possibly obeying the Jonscher law in YTiO$_{3}$. The carrier number at the highest carrier-concentration layer in YTiO$_{3}$ is estimated to be 0.015 per Ti site. Anisotropic conductivity of YTiO$_{3}$ is determined. Our study indicates that localized carriers might play an important role in the incipient formation of photoinduced metallic phases in Mott insulators. In addition, this study shows that the transfer-matrix method is effective for extracting an optical constant of a sample with a spatially inhomogeneous carrier distribution.
机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。