Atabak, M.Ünverdi O.Özer H.O.Oral, A.2016-02-082016-02-08200910711023http://hdl.handle.net/11693/22773In this work, the authors report on a quantitative investigation of lateral-force gradient and lateral force between a tungsten tip and Si (111) - (7×7) surface using combined noncontact lateral-force microscopy and scanning tunneling microscopy. Simultaneous lateral-force gradient and scanning tunneling microscopy images of single and multiatomic step are obtained. In our measurement, tunnel current is used as feedback. The lateral-stiffness contrast has been observed to be 2.5 Nm at a single atomic step, in contrast to 13 Nm at a multiatomic step on Si (111) surface. They also carried out a series of lateral stiffness-distance spectroscopy, which show a sharp increase in tip-surface interaction stiffness as the sample is approached toward the surface. © 2009 American Vacuum Society.EnglishAtomic forcesAtomic stepsForce gradientsLateral forcesLateral stiffnessLateral-force microscopiesNoncontactOff resonancesQuantitative investigationsSharp increaseSi (1 1 1)Tip-surface interactionsTungsten tipsTunnel currentsScanningScanning tunneling microscopySiliconTungstenStiffnessArticle10.1116/1.3097857