Indium Atom Manipulation on a Cleaved InAs Surface


Kyoichi Suzuki, Stefan Fölsch*, and Kiyoshi Kanisawa
Physical Science Laboratory, *Paul-Drude-Institut

 As semiconductor devices become more advanced and more highly integrated, further miniaturization and further reduction of power consumption are desired. Atomic-scale devices are the ultimate ones for meeting these demands. A promising way to construct these devices is to use a scanning probe microscope system. Up to now, we have achieved vertical manipulation of In atoms on an InAs(111)A surface by means of reversible tip-surface transfer [1]. Here we have succeeded manipulation of In atoms in not only vertical but also horizontal directions on an InAs(110) surface obtained by cleaving in ultra-high vacuum [2].
 On the InAs(111)A surface, the manipulated In atom is bound to the potential pocket originating from the surface reconstruction resulting in difficulty for the lateral manipulation. In contrast, on the InAs(110) surface, the surface reconstruction effect is small and the potential pockets are not very deep. Taking advantage of inelastic tunneling excitation and inversion asymmetry of the surface, the In atoms can be manipulated in the specific horizontal direction ([001]) (Fig. 1).
 Many compound semiconductors have same zinc-blend crystal structure as InAs. Wide and flat (110) surface can be obtained easily by cleaving. On the basis of our achievement, progress of the atom manipulation on other semiconductor (110) surfaces and on crosssectional surfaces of heterostructures is expected.
 This work was partly supported by a subsidy from the Strategic Japanese-German International Cooperative Program on Nanoelectronics supported by the Japan Science and Technology Agency (JST) and the German Research Foundation (DFG).

[1] S. Fölsch, J. Yang, C. Nacci, and K. Kanisawa, Phys. Rev. Lett. 103 (2009) 096104.
[2] K. Suzuki, S. Flösch, and K. Kanisawa, Appl. Phys. Express 4 (2011) 085002.

Fig. 1. STM images of In atoms on an InAs(110) surface. (a) and (b): In atoms are shown as black dots. When
the STM tip approaches to the surface with the negative sample voltage (-1.0 V), an atom transfers from
the tip to the surface. (c) and (d): In atoms are shown as white dots. When the tip approaches to a target
atom with the positive sample voltage (+1.0 V), the atom transfers from the surface to the tip. (e)-(g): When
the sample voltage is swept above a target atom, the atom hops horizontally in [001] direction by an In-As
zigzag row.

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