Manipulation of Cu subsurface interstitial atoms with scanning tunneling microscope

In this paper, the Cu (001) surface covered with glycylglycine has been studied by scanning tunneling microscope (STM) under ultra-high vacuum condition. On that surface copper clusters in nanometer-scale, which could form alphabet or graph at our wishes, may be produced by the scanning of STM under a certain bias voltage condition. The height of these clusters has a close relation with bias voltage, tunnel current and time. It offers the opportunity to fabricate nanometer-scale apparatus by these clusters due to their stability at room temperature. The experimental result shows that the copper atoms which form these clusters come from neither copper substrate surface nor STM tip. We think that the tensile stress field in the copper substrate is produced due to the chemisorbed glycylglycine molecule in tunnel electric field and it is the migration of copper subsurface interstitial atoms under that tensile stress field that causes the formation of copper clusters.EI02824-8315