物理学报2024，Vol.73Issue(19)：157-166,10.DOI:10.7498/aps.73.20240584
亚稳相钙钛矿稀土镍酸盐薄膜材料的可控生长与电子相变性质
Controllable growth and electronic phase transitions for metastable perovskite rare-earth nickelate films
摘要
Abstract
The multiple electronic phase transition achieved in the metastable perovskite(ReNiO3,where Re denotes a lanthanide rare-earth element)by using critical temperature,hydrogenation,electrical field and interfacial strain has attracted considerable attention in condensed matter physics and materials science,making it promising applications in the critical temperature thermistor,artificial intelligence,energy conversion and weak electric field sensing.Nevertheless,the above abundant applications are still bottlenecked by the intrinsically thermodynamic metastability related to ReNiO3.Herein,we synthesize the atomic-level flat ReNiO3 film material with thermodynamic metastability using laser molecular beam epitaxy(LMBE)that exhibits excellent thermally-driven electronic phase transitions.Notably,the interfacial heterogeneous nucleation of ReNiO3 film can be triggered by the template effect of(001)-oriented LaAlO3 substrates,owing to the similar lattice constants between LaAlO3 substrate and ReNiO3 film.In addition,we elucidate the key role of in situ annealing under oxygen-enriched atmosphere in stabilizing the distorted perovskite structure related to ReNiO3.Apart from the depositing process related to LMBE,the ReNiO3 with heavy rare-earth composition exhibits a more distorted NiO6 octahedron and a higher Gibbs free energy that is rather difficult to synthesize by using physical vacuum deposition.As a representative case,the in situ annealing-assisted LMBE process cannot be utilized to deposit the SmNiO3 film,in which the impurity peaks related to Re2O3 and NiO are observed in its XRD spectra.With the assistance of X-ray photoelectron spectraoscopy and near-edge X-ray absorption fine structure,the valence state of nickel for ReNiO3 is found to be+3,and the t2g6eg1 configuration is observed.Considering the highly tunable electronic orbital configuration of ReNiO3 related to the NiO6 octahedron,co-occupying the A-site of perovskite structure with Nd and Sm elements regulates the transition temperature(TMIT)for ReNiO3 within a broad temperature range.Furthermore,we demonstrate the anisotropy in the electronic phase transitions for Nd1-xSmxNiO3,in which case the TMIT achieved in the Nd1-xSmxNiO3/LaAlO3(111)heterostructure exceeds the one deposited on the(001)-oriented LaAlO3 substrate.The presently observed anisotropy in the electrical transportation for Nd1-xSmxNiO3 film material is related to the anisotropic in-plane NiO6 octahedron configuration triggered by differently oriented LaAlO3 substrates.The present work is expected to introduce a new degree of freedom to regulate the electronic phase transition,explore new electronic phase in ReNiO3 material system,and pave the way for growing atomic-level flat ReNiO3 film materials with expected electronic phase transitions.关键词
稀土功能材料/金属-绝缘体转变/稀土镍酸盐/亚稳态薄膜Key words
rare-earth functional material/metal-to-insulator transition/rare-earth nickelate/thermodynamically metastable film引用本文复制引用
周轩弛,焦勇杰..亚稳相钙钛矿稀土镍酸盐薄膜材料的可控生长与电子相变性质[J].物理学报,2024,73(19):157-166,10.基金项目
国家自然科学基金(批准号:52401240,12174237)和天津市光电检测技术与系统重点实验室开放课题(批准号:2024LODTS102)资助的课题. Project supported by the National Natural Science Foundation of China(Grant Nos.52401240,12174237)and the Open Project of Tianjin Key Laboratory of Optoelectronic Detection Technology and System,China(Grant No.2024LODTS102). （批准号:52401240,12174237）
