Bias-voltage dependent STM images from the 2–fold surface of the icosahedral Ag-In-Yb quasicrystal

Abstract

Abstract The 2–fold surface of the icosahedral (i-)Ag–In–Yb quasicrystal has been investigated using scanning tunnelling microscopy (STM). STM data reveals a bias-voltage dependency. At high positive bias, bright protrusions are observed. At negative bias, new protrusions appear while the size of the original protrusions decreases. The STM features at both positive and negative bias polarities can be related to atomic planes intersecting the centre of Tsai-type clusters (the building blocks of the bulk structure). The bias-dependency can be explained by a change in contribution in tunnelling current from Yb and Ag/In, as expected from density of states calculations.