@article {85,
	title = {Atomic force microscope{\textendash}force mapping and profiling on a sub 100{\r A} scale},
	journal = {Journal of Applied Physics},
	volume = {61},
	year = {1987},
	month = {01/1987},
	pages = {4723},
	abstract = {<p>A modified version of the atomic force microscope is introduced that enables a precise measurement of the force between a tip and a sample over a tip-sample distance range of 30\&ndash;150\&Aring;. As an application, the force signal is used to maintain the tip-sample spacing constant, so that profiling can be achieved with a spatial resolution of 50\&Aring;. A second scheme allows the simultaneous measurement of force and surface profile; this scheme has been used to obtain material-dependent information from surfaces of electronic materials.</p>
},
	issn = {00218979},
	doi = {10.1063/1.338807},
	author = {Martin, Y. and Williams, C. C. and Wickramasinghe, H. K.}
}
