Antonio Castro Neto

@article{ISI:001403236800001,
title = {Small polarons mediated near-room-temperature metal-insulator transition in vanadium dioxide and their hopping dynamics},
author = {Xiongfang Liu and Tong Yang and Shanquan Chen and Jing Wu and Chi Sin Tang and Yuanjie Ning and Zuhuang Chen and Liang Dai and Mengxia Sun and Mingyao Chen and Kun Han and Difan Zhou and Shengwei Zeng and Shuo Sun and Sensen Li and Ming Yang and Mark B H Breese and Chuanbing Cai and Thirumalai Venkatesan and Andrew T S Wee and Xinmao Yin},
doi = {10.1063/5.0236807},
times_cited = {0},
issn = {1931-9401},
year = {2025},
date = {2025-03-01},
journal = {APPLIED PHYSICS REVIEWS},
volume = {12},
number = {1},
publisher = {AIP Publishing},
address = {1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA},
abstract = {Researchers pursuing advanced photoelectric devices have discovered near room-temperature metal-insulator transitions (MIT) in nonvolatile VO2. Despite theoretical investigations suggesting that polaron dynamics mediate the MIT, direct experimental evidence remains scarce. In this study, we present direct evidence of the polaron state in insulating VO2 through high-resolution spectroscopic ellipsometry measurements and first-principles calculations. We illustrate the complementary role of polaron dynamics in facilitating Peierls and Mott transitions, thereby contributing to the MIT processes. Furthermore, our observations and characterizations of conventional metallic and correlated plasmons in the respective phases of the VO2 film offer valuable insight into their electron structures. This investigation enhances comprehension of the MIT mechanism in correlated systems and underscores the roles of polarons, lattice distortions, and electron correlations in facilitating phase transition processes in strongly correlated systems. Additionally, the detailed detection of small polarons and plasmons serves as inspiration for the development of new device functionalities.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{ISI:001324763700001,
title = {Uncovering an Interfacial Band Resulting from Orbital Hybridization in Nickelate Heterostructures},
author = {Mingyao Chen and Huimin Liu and Xu He and Minjuan Li and Chi Sin Tang and Mengxia Sun and Krishna Prasad Koirala and Mark E Bowden and Yangyang Li and Xiongfang Liu and Difan Zhou and Shuo Sun and Mark B H Breese and Chuanbing Cai and Le Wang and Yingge Du and Andrew T S Wee and Xinmao Yin},
doi = {10.1021/acsnano.4c09921},
times_cited = {0},
issn = {1936-0851},
year = {2024},
date = {2024-09-26},
journal = {ACS NANO},
volume = {18},
number = {40},
pages = {27707-27717},
publisher = {AMER CHEMICAL SOC},
address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
abstract = {The interaction of atomic orbitals at the interface of perovskite oxide heterostructures has been investigated for its profound impact on the band structures and electronic properties, giving rise to unique electronic states and a variety of tunable functionalities. In this study, we conducted an extensive investigation of the optical and electronic properties of epitaxial NdNiO3 synthesized on a series of single-crystal substrates. Unlike nanofilms synthesized on other substrates, NdNiO3 on SrTiO3 (NNO/STO) gives rise to a unique band structure featuring an additional unoccupied band situated above the Fermi level. Our comprehensive investigation, which incorporated a wide array of experimental techniques and density functional theory calculations, revealed that the emergence of the interfacial band structure is primarily driven by orbital hybridization between the Ti 3d orbitals of the STO substrate and the O 2p orbitals of the NNO thin film. Furthermore, exciton peaks have been detected in the optical spectra of the NNO/STO film, attributable to the pronounced electron-electron (e-e) and electron-hole (e-h) interactions propagating from the STO substrate into the NNO film. These findings underscore the substantial influence of interfacial orbital hybridization on the electronic structure of oxide thin films, thereby offering key insights into tuning their interfacial properties.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{ISI:001235219700001,
title = {Tunable Collective Excitations in Epitaxial Perovskite Nickelates},
author = {Mengxia Sun and Xu He and Mingyao Chen and Chi Sin Tang and Xiongfang Liu and Liang Dai and Jishan Liu and Zhigang Zeng and Shuo Sun and Mark B H Breese and Chuanbing Cai and Le Wang and Yingge Du and Andrew T S Wee and Xinmao Yin},
doi = {10.1021/acsphotonics.4c00210},
times_cited = {0},
issn = {2330-4022},
year = {2024},
date = {2024-05-29},
journal = {ACS PHOTONICS},
volume = {11},
number = {6},
pages = {2324-2334},
publisher = {AMER CHEMICAL SOC},
address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
abstract = {The formation of plasmons through the collective excitation of charge density has generated intense discussions, offering insights into fundamental sciences and potential applications. While the underlying physical principles have been well-established, the effects of many-body interactions and orbital hybridization on plasmonic dynamics remain understudied. In this work, we present the observation of conventional metallic and correlated plasmons in epitaxial La1-xSrxNiO3 (LSNO) films with varying Sr doping concentrations (x = 0, 0.125, 0.25), unveiling their intriguing evolution. Unlike samples at other doping concentrations, the x = 0.125 intermediate doping sample does not exhibit the correlated plasmons despite showing high optical conductivity. Through a comprehensive experimental investigation using spectroscopic ellipsometry and X-ray absorption spectroscopy, the O2p-Ni3d orbital hybridization for LSNO with a doping concentration of x = 0.125 is found to be significantly enhanced, alongside a considerable weakening of its effective correlation U*. These factors account for the absence of correlated plasmons and the high optical conductivity observed in LSNO (0.125). Our results underscore the profound impact of orbital hybridization on the electronic structure and the formation of plasmons in strongly correlated systems. This in turn suggests that LSNO could serve as a promising alternative material in optoelectronic devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}