@article{Tang2023,
title = {Detection of two-dimensional small polarons at oxide interfaces by optical spectroscopy},
author = {Chi Sin Tang and Shengwei Zeng and Jing Wu and Shunfeng Chen and Muhammad A. Naradipa and Dongsheng Song and Milorad V. Milošević and Ping Yang and Caozheng Diao and Jun Zhou and Stephen J. Pennycook and Mark B. H. Breese and Chuanbing Cai and Thirumalai Venkatesan and Ariando Ariando and Ming Yang and Andrew T. S. Wee and Xinmao Yin},
doi = {10.1063/5.0141814},
issn = {1931-9401},
year = {2023},
date = {2023-09-01},
urldate = {2023-09-01},
volume = {10},
number = {3},
publisher = {AIP Publishing},
abstract = {Two-dimensional (2D) perovskite oxide interfaces are ideal systems to uncover diverse emergent properties, such as the arising polaronic properties from short-range charge–lattice interactions. Thus, a technique to detect this quasiparticle phenomenon at the buried interface is highly coveted. Here, we report the observation of 2D small-polarons at the LaAlO3/SrTiO3 conducting interface using high-resolution spectroscopic ellipsometry. First-principles investigations show that interfacial electron–lattice coupling mediated by the longitudinal phonon mode facilitates the formation of these polarons. This study resolves the long-standing question by attributing the formation of interfacial 2D small polarons to the significant mismatch between experimentally measured interfacial carrier density and theoretical values. Our study sheds light on the complexity of broken periodic lattice-induced quasi-particle effects and its relationship with exotic phenomena at complex oxide interfaces. Meanwhile, this work establishes spectroscopic ellipsometry as a useful technique to detect and locate optical evidence of polaronic states and other emerging quantum properties at the buried interface.},
keywords = {General Physics and Astronomy},
pubstate = {published},
tppubtype = {article}
}
