Comparative Scanning Tunneling Microscopy Study on Hexaborides

• Published in: physica status solidi (b) 2021-01, Vol.258 (1), p.n/a
• Main Authors: Wirth, Steffen, Rößler, Sahana, Jiao, Lin, Ale Crivillero, Maria Victoria, Rosa, Priscila F. S., Fisk, Zachary
• Format: Article
• Language: English
• Subjects: hexaborides; scanning tunneling microscopy and spectroscopy; surface terminations
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.202000022

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. The surfaces of hexaborides SmB6 and EuB6 both show a number of terminations, the assignment of which is important for the interpretation of results, specifically if surface‐sensitive tools are utilized. Dual‐bias mode scanning tunneling microscopy is used to enable a comparison of topographies obtained with different bias voltages. Particularly intriguing results are obtained using magnetic tunneling tips.