Revealing the Interaction of Charge Carrier–Phonon Coupling by Quantification of Electronic Properties at the SrTiO3/TiO2 Heterointerface
Revealing the Interaction of Charge Carrier–Phonon Coupling by Quantification of Electronic Properties at the SrTiO3/TiO2 Heterointerface
复制标题
通过量化 SrTiO3/TiO2 异质界面的电子特性揭示电荷载流子与声子耦合的相互作用
DOI：
10.1021/acs.nanolett.1c04698
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发表时间：
2022
期刊：
影响因子：
10.8
通讯作者：
Zhong-Qun Tian
中科院分区：
文献类型：
--
作者：
Ting-Xiao Qin;En-Ming You;Jia-Ye Zhang;Hai-Long Wang;Kelvin H. L. Zhang;Bing-Wei Mao;Zhong-Qun Tian
具有高载流子密度的氧化物异质界面可以与晶格声子产生强烈的相互作用，产生相当大的等离子体-声子耦合，从而扰乱了迷人的光学和电子特性，如二维电子气体、铁磁性和超导性。本文采用基于散射型扫描近场光学显微镜（s-SNOM）的红外光谱纳米成像技术，定量研究了SrTiO3/TiO2界面上电子-声子耦合的相互作用和局部载流子的空间分布。我们发现在异质界面附近，高频介电常数（ε∞= 7.1 ~ 9.0）和载流子密度（n = 6.5 × 1019 ~ 1.5 × 1020 cm-3）增加。此外，利用单色近场成像技术提取了异质界面上载流子密度与延伸厚度之间的定量信息。直接评价异质界面厚度与电荷载流子-声子耦合相互作用之间的关系，将为氧化物基电子器件的开发提供有价值的信息。
Oxide heterointerfaces with high carrier density can interact strongly with the lattice phonons, generating considerable plasmon–phonon coupling and thereby perturbing the fascinating optical and electronic properties, such as two-dimensional electron gas, ferromagnetism, and superconductivity. Here we use infrared-spectroscopic nanoimaging based on scattering-type scanning near-field optical microscopy (s-SNOM) to quantify the interaction of electron–phonon coupling and the spatial distribution of local charge carriers at the SrTiO3/TiO2 interface. We found an increased high-frequency dielectric constant (ε∞ = 7.1–9.0) and charge carrier density (n = 6.5 × 1019 to 1.5 × 1020 cm–3) near the heterointerface. Moreover, quantitative information between the charge carrier density and extension thickness across the heterointerface has been extracted by monochromatic near-field imaging. A direct evaluation of the relationship between the thickness and the interaction of charge carrier–phonon coupling of the heterointerface would provide valuable information for the development of oxide-based electronic devices.