We describe an undergraduate laboratory experiment on conductance steps observed to occur near integer multiples of as nanocontacts form and break between gold wires in loose contact. This experimental arrangement was first described by Costa-Krämer et al. [Surf. Sci. 342, L1144 (1995)]. A simple op-amp circuit in conjunction with an inexpensive storage oscilloscope suffice to observe the steps. The experiment may be extended by interfacing to a computer, which accumulates a histogram of conductance values as the wires are brought into and out of contact many times. The histogram shows peaks near integer multiples of We emphasize the pedagogical issues involved in bringing an experiment from forefront condensed-matter physics research into the undergraduate laboratory.
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© 1999 American Association of Physics Teachers.
1999
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