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Title: Robust topological surface state in Kondo insulator SmB{sub 6} thin films

Fabrication of smooth thin films of topological insulators with true insulating bulk are extremely important for utilizing their novel properties in quantum and spintronic devices. Here, we report the growth of crystalline thin films of SmB{sub 6}, a topological Kondo insulator with true insulating bulk, by co-sputtering both SmB{sub 6} and B targets. X-ray diffraction, Raman spectroscopy, and transmission electron microscopy indicate films that are polycrystalline with a (001) preferred orientation. When cooling down, resistivity ρ shows an increase around 50 K and saturation below 10 K, consistent with the opening of the hybridization gap and surface dominated transport, respectively. The ratio ρ{sub 2K}/ρ{sub 300K} is only about two, much smaller than that of bulk, which indicates a much larger surface-to-bulk ratio. Point contact spectroscopy using a superconductor tip on SmB{sub 6} films shows both a Kondo Fano resonance and Andeev reflection, indicating an insulating Kondo lattice with metallic surface states.
Authors:
; ; ;  [1] ;  [2] ; ;  [3] ; ;  [4] ;  [5] ;  [1] ;  [2]
  1. Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742 (United States)
  2. (United States)
  3. Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708 (United States)
  4. Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)
  5. Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742 (United States)
Publication Date:
OSTI Identifier:
22402410
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; GRAIN ORIENTATION; KONDO EFFECT; POLYCRYSTALS; RAMAN SPECTROSCOPY; SAMARIUM BORIDES; SEMICONDUCTOR MATERIALS; SPUTTERING; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION