Crystal Structure and Electronic Property Modification of Ca2RuO4 thin Films via Fluorine Doping
Crystal Structure and Electronic Property Modification of Ca2RuO4 thin Films via Fluorine Doping
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氟掺杂对 Ca2RuO4 薄膜的晶体结构和电子性能改性
DOI：
10.1103/physrevmaterials.6.035002
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
and T. Hasegawa
中科院分区：
文献类型：
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作者：
S. Fukuma;A. Chikamatsu;T. Katayama;T. Maruyama;K. Yanagisawa ;K. Kimoto;M. Kitamura;K. Horiba;H. Kumigashira;Y. Hirose;and T. Hasegawa
层状Ru氧氟化物具有不同的晶体结构和Ru的氧化态，并显示出独特的物理性质。虽然据报道，各种层状Ruthenate已与锶配位进行了局部化学氟化，但对含有较小Ca离子的层状Ruthenate的氟化还缺乏研究。在本文中，我们用聚偏氟乙烯对前驱体进行表面化学氟化，在(001)衬底上制备了相纯的单晶薄膜。X射线能谱和光电子能谱分析表明，所制得的氟化薄膜的化学成分与状态一致，而真空氟化制备的薄膜的化学成分为。扫描电子显微镜显示，在CaO岩盐区块中只有1个位置，而在SRO层中有两个不同的位置。薄膜具有绝缘性，其电阻率(ρ)为300K，并且ρ的温度行为可用二维变程跳跃模型很好地描述。这些结果表明，局部扭曲是控制Ruthenate拓扑化学氟化的一个重要因素，并影响反应物的晶体结构和电子结构。
Layered ruthenium oxyfluorides have various crystal structures and Ru oxidation states and exhibit unique physical properties. While various layered ruthenates have reportedly been topochemically fluorinated with Sr assites, investigation of the fluorination of layered ruthenates containing smaller Ca ions is lacking. In this paper, we fabricated phase-pure and single-crystalline thin films ofon(001) substrates via topochemical fluorination of theprecursor using polyvinylidene fluoride. The obtained fluorinated thin films had a chemical composition ofwith thestate, as determined by energy-dispersive x-ray spectroscopy and x-ray photoemission spectroscopy, whereas the film prepared viafluorination had a composition of. Scanning transmission electron microscopy revealed thathas only 1site in CaO rock-salt blocks, whereashas two inequivalentsites in the SrO layers. Thefilm was insulating, with a resistivity (ρ) ofat 300 K. Moreover, the temperature behavior of ρ was well described by the two-dimensional variable range hopping model. These results demonstrate that local distortion is an important factor that governs the topochemical fluorination of ruthenates and affects the crystal and electronic structures of the reactants.