The role of surface elasticity in giant corrugations observed by scanning tunneling microscopes

Due to the importance of scanning tunneling microscopy for atomic scale research the anomalously high corrugation values on close packed metal surfaces have been the subject of debate and extensive theoretical work in the past two decades. To date it remained unclear, how surface properties and electronic structures are related to forces and interactions. Here we show that elasticity, in particular the high elasticity of aluminum surfaces, enhances corrugation by up to one order of magnitude. The parameterfree simulations yield correct results for all close packed metal surfaces and emphasize the importance of atomic relaxations for chemisorption processes. � 2004 Elsevier B.V. All rights reserved. It is an astonishing fact that every second paper on surface chemistry or physics today is based on scanning tunneling microscopy (STM) experiments. The versatility of STM mostly derives from its ability to probe into most of the surface properties at the atomic scale. It has been shown conclusively, that it cannot only resolve atomic positions, but also their chemical nature [1], their chemical environment [2], magnetization [3], and even two dimensional surface states [4]. By contrast, STM theory has long been focused on electronic surface properties alone [5]. The method, even though it is generally reliable, involves as free parameter the distance between the two surfaces, which can be used to adjust simulated density contours to constant current linescans. In the estimates the actual distance between the atomic cores of surface and tip atoms varies widely from less than 300 to more than 1000 pm [6,7]. This distance range covers more than seven orders of magnitude in the tunnel

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