钙钛矿结构4d过渡金属锝氧化物的表面/界面性质的理论研究

项目名称： 钙钛矿结构4d过渡金属锝氧化物的表面/界面性质的理论研究

项目编号： No.11247023

项目类型： 专项基金项目

立项/批准年度： 2013

项目学科： 物理学II

项目作者： 马春兰

作者单位： 苏州科技学院

项目金额： 20万元

中文摘要： 钙钛矿结构3d过渡金属氧化物（TMO）因具有高温超导、庞磁电阻等特性已应用于各种器件，而4d TMO因最初被认为关联性较弱而受到较少的关注。去年有实验报道钙钛矿结构4d TMO SrTcO3和CaTcO3奈尔温度分别高达1023 K和800 K，而与4d TMO SrTcO3相对应的3d TMO SrMnO3的奈尔温度只有260K，可见4d锝氧化物更有希望应用于常温甚至高温环境。研究人员进一步发现特别高的奈尔温度是钙钛矿结构4d锝氧化物所特有的。为了理解此类新材料的独特性质、探索其物理机制，并为其实际应用于器件提供理论基础，我们在国内外首次提出研究其表面/界面性质。我们将结合密度泛函理论和动力学平均场理论系统研究4d TMO ATcO3 (A=Ca, Sr, Ba)表面/界面的电子态性质和输运性质。本项目对理解这类新材料的表面/界面性质及实现其在器件方面的应用都具有重要意义。

中文关键词： 过渡金属氧化物；表面；界面；奈尔温度；带隙

英文摘要： Perovskite 3d transition-metal oxides (TMO) have been applied into various devices due to their characters of high-temperature superconductivity and colossal magnetoresistance (CMR) etc., while 4d TMO have received much less attention since electron correlations in them were initially believed to be weaker. Last year it was experimentally reported that 4d TMO SrTcO3 and CaTcO3 have extremely high Neétemperatures of 1023 K and 800 K, respectively. In contrast, the Neétemperature of the analogue 3d TMO SrMnO3 is only 260 K. One can expect that 4d technetium oxides are more promissing to be used in ambient and even high temperatures. It was further found that the high Neétemperature is a unique character of 4d technetium oxides. In order to understand the special property of these 4d technetium oxides, and to explore the mechanism behind so as to provide theoretical basis for their practical applications in devices, we put forward to study the surface/interface properties of ATcO3 (A=Ca, Sr, Ba) for the first time. We plan to combine density functional theory with the dynamical mean-field theory to investigate systematically the electronic and transport properties of the ATcO3 surface and interface structures. The information from our study will be important for understanding the physical properties of this n

英文关键词： Transition-Metal Oxides；Surface；Interface；Neel Temperature；Band Gap