Study on local surface electrical conduction by scanning microscopic four-point probes in ultrahigh vacuum

超高真空中显微四点探针扫描局部表面电导研究

• 批准号: 13305004
• 负责人: HASEGAWA Shuji
• 金额: $ 25.04万
• 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 (A)
• 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/grant/KAKENHI-PROJECT-13305004/
• 关键词: Four-point probe; Metal-insulator transition; Peierls transition; Surface electrical conduction; Silicon; Surface superstructure; Weak localization; Quasi-one-dimensional metal; 2次元吸着原子ガス; 4探針; 超高真空; 光学顕微鏡; RHEED

We have developed a ultrahigh-vacuum system for electrical conductivity measurements with high surface sensitivity by using monolithic micro-four-point probe method (probe spacing being 4〜40μm) at temperatures ranging from 10 K to room temperature, combined with simultaneous structure analysis by reflection-high-energy electron diffraction (RHEED). This apparatus enables direct measurements of electrical conductivity at the topmost atomic layers on crystal surfaces as a function of temperature. We have made several new findings with this apparatus.(1)A quasi-one-dimensional metallic surface, Si(111)-4×1-In, was found to show a metal-insulator transition around 120 K as revealed by a dramatic increase in resistance by cooling. This is consistent with a picture of Peierls transition accompanied with charge-density waves.(2)A two-dimensional metallic surface, Si(111)-√3×√3-Ag, was found to show a metal-insulator transition around 230 K as revealed by a dramatic increase in resistance by cooling. Combined with photoemission spectroscopy study, the low-temperature phase is not a band insulator. Weak localization may play a role.(3)A quasi-one-dimensional metallic surface, Si(557)-Au, was found to be semiconductive in terms of electrical conduction. This may be due to atomic defects which break up the metallic atomic chains into segments.

我们开发了一种超高真空电导率测量系统，采用单片微型四点探针法（探针间距为4~40μm），温度范围为10 K至室温，并结合同步结构分析，具有高表面灵敏度。反射高能电子衍射（RHEED）可以直接测量晶体表面最顶层原子层的电导率与温度的关系。 (1) 准一维金属表面 Si(111)-4×1-In 被发现在 120 K 左右表现出金属-绝缘体转变，这通过冷却引起的电阻急剧增加表明。与伴随电荷密度波的 Peierls 跃迁图一致。(2)二维金属表面 Si(111)-√3×√3-Ag 被发现在 230 K 左右表现出金属-绝缘体转变，如下所示：结合光电子能谱研究表明，低温相不是带状绝缘体，可能起到了一定作用。(3)准一维金属表面Si(557)。 -Au，被发现在导电方面具有半导体性，这可能是由于原子缺陷将金属原子链分解成片段。

项目成果

ナノテクノロジーのための走査電子顕微鏡

用于纳米技术的扫描电子显微镜

• 发表时间: 2004
• 作者: 日本表面科学会編;長谷川修司;他 分担執筆
• 通讯作者: 他 分担執筆

長谷川修司, 白木一郎, 田邊輔仁, 保原麗, 金川泰三, 谷川雄洋, 松田巌: "ミクロな4端子プローブによる表面電気伝導の測定"表面科学. 23. 740-752 (2002)

Shuji Hasekawa、Ichiro Shiraki、Sukehito Tanabe、Rei Yasuhara、Taizo Kanakawa、Yuhiro Tanikawa、Iwao Matsuda：“使用显微 4 端子探针测量表面电导率”表面科学 23. 740-752 (2002)。

Fundamentals and Applications of Surface Science, Ed. Surface Science Society of Japan, Scanning electron microscopy for Nanotechnology

表面科学的基础和应用，Ed。

• 发表时间: 2004
• 期刊: Maruzen
• 作者: S. Hasegawa;et. al.
• 通讯作者: et. al.

S.Hasegawa, I.Shiraki, T.Tanikawa, C.L.Petersen, et al.: "Direct measurement of surface-state conductance by microscopic four-point probe method"Journal of Physics : Condensed Matter. 14. 8379-8392 (2002)

S.Hasekawa、I.Shiraki、T.Tanikawa、C.L.Petersen 等人：“通过显微四点探针法直接测量表面态电导”物理学杂志：凝聚态物质。

S.V.Ryjkov, T.Nagao, V.G.Lifshits, S.Hasegawa: "Phase transition and stability of Si(111)-8x'2'-In surface phase at low temperature"Surface Science. 488. 15-22 (2001)

S.V.Ryjkov、T.Nagao、V.G.Lifshits、S.Hasekawa：“低温下 Si(111)-8x2-In 表面相的相变和稳定性”表面科学。