Olsson, Fredrik E. and Persson, Mats and Repp, Jascha and Meyer, Gerhard (2005) Scanning tunneling microscopy and spectroscopy of NaCl overlayers on the stepped Cu(311) surface: Experimental and theoretical study. Physical Review B 71 (7), 075419.
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The physical properties of ultrathin NaCl overlayers on the stepped Cu(311) surface have been characterized using scanning tunneling microscopy (STM) and spectroscopy, and density-functional calculations. Simulations of STM images and differential conductance spectra were based on the Tersoff-Hamann approximation for tunneling with corrections for the modified tunneling barrier at larger voltages and calculated Kohn-Sham states. Characteristic features observed in the STM images can be directly related to calculated electronic and geometric properties of the overlayers. The measured apparent barrier heights for the mono-, bi-, and trilayers of NaCl and the corresponding adsorption-induced changes in the work function, as obtained from the distance dependence of the tunneling current, are well reproduced and explained by the calculated results. The measurements revealed a large reduction of the tunneling conductance in a large voltage range, resembling a band gap. However, the simulated spectrum showed that only the onset at positive sample voltages may be viewed as a valence-band edge, whereas the onset at negative voltages is caused by the drastic effect of the electric field from the tip on the tunneling barrier.
|Date:||24 February 2005|
|Institutions:||Physics > Institute of Experimental and Applied Physics > Chair Professor Giessibl > Group Jascha Repp|
|Subjects:||500 Science > 530 Physics|
|Created at the University of Regensburg:||Unknown|
|Deposited On:||03 Jul 2012 11:17|
|Last Modified:||10 Feb 2014 11:28|