Comparative Scanning Tunneling Microscopy Study on Hexaborides

Abstract

Scanning tunneling microscopy (STM) investigations on two hexaboride compounds, SmB6 and EuB6, are compared in an effort to provide a comprehensive picture of their surface structural properties. The latter is of particular importance for studying the nature of the surface states in SmB6 by surface-sensitive tools. Beyond the often encountered atomically rough surface topographies of in situ, low-temperature cleaved samples, differently reconstructed as well as B-terminated and, more rarely, rare-earth terminated areas can be found. With all the different surface topographies observed on both hexaborides, a reliable assignment of the surface terminations is brought forward.