INTERPRETATION OF THE SCANNING TUNNELING AND ATOMIC-FORCE MICROSCOPY IMAGES OF LAYERED COMPOUND TLSBSE2 BY ELECTRON-DENSITY CALCULATIONS

Atomic-scale scanning tunneling microscopy (STM) and atomic force micr oscopy (AFM) images were obtained for layered compound TlSbSe2. This c ompound consists of two slightly different TlSbSe2 layers, and the sur faces of these layers have three different atoms. The observed STM and AFM images were analyzed by calculating the partial electron density p-(r0,e(f)) and the total electron density p(ro) of individual TlSbSe2 layers. In both STM and AFM images, the brightest spots are associate d with the most protruded surface atoms, i.e., the TI atoms. For vario us bias voltages employed, there occurs no atom-selective imaging in t he STM images.