Device Physics of Strongly Correlated Semiconductor

强相关半导体器件物理

• 批准号: 13440109
• 负责人: TAKAGI Hidenori
• 金额: $ 9.86万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13440109/
• 关键词: Mott insulator; physics of Semiconductor Devices; Carrier Doping; nano-scale variation of electronic; charge ordering; Field Effect Transistor (FET) Structure; transition metal oxides.; 電荷効果トランジスタ; モット半導体; キャリアドーピグ; Ca_<2-x>Na_xCuO_2Cl_2; 電界効果型

The aim of this research project is to explore the device physics of strongly correlated semiconductors. One of the major targets was the impurity effect. As a prototypical system, lightly doped Mott insulator Ca_<2-x>Na_xCuO_2Cl_2 was studied. We found a non-scale self-organization of electrons associated with doping by STM/STS and finally identified it as a checkerboard type charge ordering, which we believe is at the heart of cuprate physics including large psedo-gap phenomena. We also find nano-scale variation of electronic states around the impurities in nearly ferromagnetic ruthenates, which represents an important step to establish physics of impurity states in strongly correlated electron systems. The other major targets was fabrication of oxide device, in particular field effect transistor (FET). We have successfully fabricated SrTiO_3 perovskite FET, which shows well defined FET characteristics such as the saturation of drain current. Even better performance was achieved in another perovskite oxide KTaO_3, which showed ON/OFF rationof 1000 and the field effect mobility of 0.4 cm^2/Vsec comparable with those of organic FET. These devices can work at a cryogenic temperature as low as 2K and the presence of metallic channel was confirmed. These results opened door for FET "chemistry" of exotic transition metal oxides.

本研究项目的目的是探索强关联半导体的器件物理。主要目标之一是杂质效应。作为一个典型的系统，轻掺杂的Mott绝缘体Ca_<2-x>Na_xCuO_2Cl_2进行了研究。我们发现了与STM/STS掺杂相关的电子的非标度自组织，并最终将其确定为棋盘式电荷有序，我们认为这是铜酸盐物理学的核心，包括大的假能隙现象。我们还发现了近铁磁双烯酸盐中杂质周围电子态的纳米尺度变化，这代表了在强关联电子系统中建立杂质态物理的重要一步。另一个主要目标是制造氧化物器件，特别是场效应晶体管（FET）。我们已经成功地制备了SrTiO_3钙钛矿FET，它表现出良好的FET特性，如漏电流饱和。在另一种钙钛矿氧化物KTaO_3中获得了更好的性能，其显示出1000的开/关比和0.4 cm^2/Vsec的场效应迁移率，与有机FET相当。这些器件可以在低温2K下工作，并证实了金属通道的存在。这些结果为外来过渡金属氧化物的FET“化学”打开了大门。

项目成果

Katsufuji T et al.: "Coupling between magnetism and dielectric properties in quantum paraelectric EuTiO_3"PHYS REV B. 64・05. 4415-4418 (2001)

Katsufuji T 等人：“量子顺电 EuTiO_3 中的磁性与介电特性之间的耦合” PHYS REV B. 4415-4418 (2001)。

Yuhki Kohsaka, Masaki Azuma Ikuya Yamada, Takao Sasagawa, Tetsuo Hanaguri, Mikio Takano, Hidenori Takagi: "Growth of Na-Doped Ca_2CuO_2Cl_2 Single Crystals under High Pressures of Several GPa"J.Am.Chem.Soc. Vol.124, No.41. 12275-12278 (2002)

Yuhki Kohsaka、Masaki Azuma Ikuya Yamada、Takao Sasakawa、Tetsuo Hanaguri、Mikio Takano、Hidenori Takagi：“在几 GPa 的高压下生长 Na 掺杂 Ca_2CuO_2Cl_2 单晶”J.Am.Chem.Soc。

Ueda H, Kitazawa K, Matsumoto T, Takagi H: "Charge transport near pressure-induced antiferromagnetic quantum critical point in Magneli-phase vanadium oxides"Solid State Communications. 125:(2). 83-87 (2003)

Ueda H、Kitazawa K、Matsumoto T、Takagi H：“Magneli 相钒氧化物中压力诱导反铁磁量子临界点附近的电荷传输”固态通信。

Katsufuji T et al.: "Dielectric and magnetic anomalies and spin frustration in hexagonal RMnO_3 (R = Y, Yb, and Lu)"PHYS REV B. 64-10. 4419-4422 (2001)

Katsufuji T 等人：“六方 RMnO_3（R = Y、Yb 和 Lu）中的介电和磁异常以及自旋挫败”PHYS REV B. 64-10。

Matsuno K, et al.: "Charge ordering in the geometrically frustrated spinel AIV_2O_4"J PHYS SOC JPN. 70・6. 1456-1459 (2001)

Matsuno K 等人：“几何挫败尖晶石 AIV_2O_4 中的电荷排序”J PHYS SOC JPN 70・6（2001）。