Quantum Contact

量子接触

• 批准号: 12002005
• 负责人: TAKAYANAGI Kunio
• 金额: $ 229.44万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Specially Promoted Research
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12002005/
• 关键词: Quantum Point Contact; Ballistic transport; Nonlinear conductance; Super ionic conductor; Helical multi-shell nanowire; Atomic chain; 電子顕微鏡; 走査トンネル顕微鏡; 原子間力顕微鏡; ナノワイヤ; 量子化コンダクタンス; 表面; 走査型トンネル顕微鏡; ナノワイヤー; 融体; 量子コンタクト; 量子化電気伝導

The present work clarified the quantum mechanical phenomena at the quantum nano-contact, such as quantized conductance, by using STM (scanning tunneling microscope) installed in the specimen position of the UHV (ultra-high-vacuum) transmission electron microscope (TEM). A new AFM (atomic force microscope) combined UHV-TEM was also developed to study atomic forces acting on the nano-contact or on the nanowire that span between the AFM cantilever and the substrate.Some noticeable results are obtained as follows :(1)The conductance of the helical multi-shell (HMS) gold nanowire with magic number 7 was measured by using STM-TEM, to conclude that the integer quantization of the conductance is broken because of the symmetry breaking at the contact area of the electrode and the HMS. (2)Single wall nanotube of gold (and platinum) was synthesized at 150K during the thinning of the gold film by electron beam. (3)Copper nanowires display half integer quantum conductance, but they allow no change under application of magnetic filed up to 100mT. (4)Non-linear conductance was recognized for gold, copper, silver, and platinum nano-contacts. The conductance increased positively for increasing the bias voltage. (5)The breaking of the conductance quantization was investigated by making a long silver nanowire (rope), which grew from the AgI crystalline surface while the tip electrode approached above the AgI surface. (5)We developed Cs (spherical aberration) corrected lens for the analysis of elements at nano-contacts to study electron scattering at atoms in the nano-contact.

利用安装在超高真空透射电子显微镜（TEM）样品位上的扫描隧道显微镜（STM）研究了量子纳米接触中的量子力学现象，如量子化电导。利用原子力显微镜（AFM）结合超高压透射电镜（UHV-TEM）研究了原子力作用于纳米接触或纳米线上的力，得到了如下重要结果：（1）利用STM-TEM测量了幻数为7的螺旋多壳层（HMS）金纳米线的电导，发现电导的整数量子化是由于电极与HMS接触区域的对称性破缺所致。（2）在电子束减薄金膜的过程中，在150 K下合成了金（铂）单壁纳米管。（3）铜纳米线表现出半整数量子电导，但在100 mT的磁场作用下电导基本不变。（4）对于金、铜、银和铂纳米接触，认识到非线性电导。随着偏压的增加，电导正向增加。（5）通过制备长的银纳米线（绳）来研究电导量子化的破坏，所述长的银纳米线（绳）从AgI晶体表面生长，而尖端电极接近AgI表面。(5)We为了研究电子在纳米接触原子上的散射，研制了用于纳米接触处元素分析的Cs（球面像差）校正透镜。

项目成果

Yoshifumi Oshima, Akiko Onga, Kunio Takayanagi: "Helical gold nanotube synthesized at 150K"Phys.Rev.Lett.. 91. 205503(4) (2003)

Yoshifumi Oshima、Akiko Onga、Kunio Takayanagi：“在 150K 下合成的螺旋金纳米管”Phys.Rev.Lett.. 91. 205503(4) (2003)

谷城康眞, 有本明希子, 高柳邦夫: "超イオン導電体AgIからの銀細線の成長と電気伝導"真空. 46[3](to be published). (2003)

Yasumasa Tanishiro、Akiko Arimoto、Kunio Takayanagi：“超离子导体 AgI 的细银线的生长和导电” 46[3]（待出版）。

Y.Naitoh, K.Takayanagi, Y.Oshima, H.Hirayama: "Simultaneous STM and UHV electron microscope observation of silicon nanowires extracted from Si(111) surface"J.Electron.Micro.. 49. 211-216 (2000)

Y.Naitoh、K.Takayanagi、Y.Oshima、H.Hirayama：“同时 STM 和 UHV 电子显微镜观察从 Si(111) 表面提取的硅纳米线”J.Electron.Micro.. 49. 211-216 (2000)

Y.Ohshima, H.Koizumi, Y.Kondo, K.Mouri, H.Hirayama, K.Takayangi: "Evidence of a Single Wall Platinum Nano-tube"Phys.Rev.B. 65. 121401 (2002)

Y.Ohshima、H.Koizumi、Y.Kondo、K.Mouri、H.Hirayama、K.Takayangi：“单壁铂​​纳米管的证据”Phys.Rev.B。

Y.Ohshima, T.Nangou, H.Hirayama, K.Takayanagi: "Face centered cubic indium nano-particles studied by UHV-transmission electron microscopy"Surface Science. 476. 107-114 (2001)

Y.Ohshima、T.Nangou、H.Hirayama、K.Takayanagi：“通过特高压透射电子显微镜研究面心立方铟纳米粒子”表面科学。