Field-effect doping of strongly correlated electron systems

强相关电子系统的场效应掺杂

• 批准号: 17340105
• 负责人: LIPPMAA Mikk
• 金额: $ 9.92万
• 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: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17340105/
• 关键词: oxide; field effect; transistor; metal-insulator transition; SrTiO3; mobility; superconductivity; nanowire; 強相関エレクトロニクス; マイクロ・ナノデバイス; MBE、エピタキシャル; 先端機能デバイス; 超薄膜

During H18 we succeeded in fabricating SrTiO3-based field-effect transistors with epitaxial and amorphous CaHfO3 and DyScO3 gate insulator layers. Epitaxial insulator layers of CaHfO3 and DyScO3 could be grown on SrTiO3 to a thickness of about 2 nm without nucleating grain boundaries. By combining a thin epitaxial layer with an amorphous insulator, we achieved transistors where sheet carrier densities of 10^<13> cm^<-2> order could be induced in a thin surface layer of a SrTiO_3 substrate. A rapid increase of the field-effect mobility was observed at low temperature, indicating that the field-induced carriers are equivalent to chemically doped carriers. A metal-to-insulator transition was observed in the SrTiO_3 transistors.The growth of metallic LaTiO_3 nanowires was studied. A step-flow growth technique was developed that allowed us to fabricate an array of metallic (La, Sr)TiO_3 nanowires along the step edges of an annealed SrTiO_3 substrate. A technique was developed to buffer the surface of an annealed SrTiO_3 single crystal surface with a SrO film pror to the growth of the LaTiO_3 nanowires. This step was necessary in order to reduce the surface conductivity of SrTiO_3 and thus isolate the nanowires from each other. The final nanowire arrays showed nearly ideal one-dimensional conductivity.The superconducting properties of Nb-doped SrTiO_3 films were studied in collaboration with the group of prof. Triscone at the University of Geneva, Switzerland. We succeeded in fabricating superconducting Nb:SrTiO_3 thin films and demonstrated that the superconductivity can be switched on and off by changing the carrier concentration in the thin films by electrostatic field effect.

在H18期间，我们成功地制造了具有外延和非晶CaHfO3和DyScO3栅极绝缘层的SrTiO3基场效应晶体管。 CaHfO3 和 DyScO3 的外延绝缘体层可以在 SrTiO3 上生长至约 2 nm 的厚度，而不会在晶界成核。通过将薄外延层与非晶绝缘体相结合，我们实现了可以在 SrTiO_3 衬底的薄表面层中感应出 10^<13>cm^-2> 量级的片状载流子密度的晶体管。在低温下观察到场效应迁移率快速增加，表明场致载流子相当于化学掺杂载流子。在SrTiO_3晶体管中观察到金属到绝缘体的转变。研究了金属LaTiO_3纳米线的生长。开发了一种阶梯流生长技术，使我们能够沿着退火的 SrTiO_3 基板的阶梯边缘制造金属 (La, Sr)TiO_3 纳米线阵列。开发了一种技术，用 SrO 薄膜缓冲退火的 SrTiO_3 单晶表面，以促进 LaTiO_3 纳米线的生长。为了降低 SrTiO_3 的表面电导率，从而使纳米线彼此隔离，该步骤是必要的。最终的纳米线阵列表现出近乎理想的一维电导率。与教授课题组合作研究了Nb掺杂SrTiO_3薄膜的超导性能。瑞士日内瓦大学的 Triscone。我们成功地制备了超导Nb:SrTiO_3薄膜，并证明通过静电场效应改变薄膜中的载流子浓度可以开启和关闭超导性。

项目成果

In situ resonant photoemission characterization of LaO.6SrO.4MnO3 layers buried in insulating perovskite oxides

埋在绝缘钙钛矿氧化物中的 LaO.6SrO.4MnO3 层的原位谐振光电发射表征

• 发表时间: 2006
• 期刊: JOURNAL OF APPLIED PHYSICS 99・8
• 作者: Kumigashira H;Hashimoto R;Chikamatsu A;Oshima M;Ohnishi T;Lippmaa M;Wadati H;Fujimori A;Ono K;Kawasaki M;Koinuma H
• 通讯作者: Koinuma H

Flux-assisted reactive solid phase epitaxy of highly c-axis oriented Ru(Eu_<1.5>Ce_<0.5>) Sr_2Cu20_<10-δ> thin films

高c轴取向Ru(Eu_<1.5>Ce_<0.5>)Sr_2Cu20_<10-δ>薄膜的助熔剂辅助反应固相外延

• 发表时间: 2005
• 期刊: Physica C : Superconductivity Vol.422,Issue 1-2
• 作者: W.Q.Lu;H.Koinuma;K.Shibuya;M.Lippmaa;et al.
• 通讯作者: et al.

In vacuo photoemission study of atomically controlled La1-xSrxMnO3 thin films : Composition dependence of the electronic structure

原子控制 La1-xSrxMnO3 薄膜的真空光电发射研究：电子结构的成分依赖性

• 发表时间: 2005
• 期刊: Phys.Rev.B 71
• 作者: K.Horiba;H.Kumigashira;M.Oshima;et al.
• 通讯作者: et al.

Sr surface segregation and water cleaning for atomically controlled SrTiO3(001) substrates studied by photoemission spectroscopy

• DOI: 10.1016/j.elspec.2005.01.167
• 发表时间: 2005-06
• 期刊: Journal of Electron Spectroscopy and Related Phenomena
• 影响因子: 1.9
• 作者: D. Kobayashi;R. Hashimoto;A. Chikamatsu;H. Kumigashira;M. Oshima;T. Ohnishi;M. Lippmaa;K. Ono;M. Kawasaki;H. Koinuma

Field-effect modulation of the transport properties of nondoped SrTiO3

• DOI: 10.1063/1.2207502
• 发表时间: 2006-05
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: K. Shibuya;T. Ohnishi;T. Uozumi;Taisuke Sato;M. Lippmaa;M. Kawasaki;K. Nakajima;T. Chikyow;H. Koinuma