skip to main content

SciTech ConnectSciTech Connect

Title: Magnetic modulation doping in topological insulators toward higher-temperature quantum anomalous Hall effect

Quantum anomalous Hall effect (QAHE), which generates dissipation-less edge current without external magnetic field, is observed in magnetic-ion doped topological insulators (TIs) such as Cr- and V-doped (Bi,Sb){sub 2}Te{sub 3}. The QAHE emerges when the Fermi level is inside the magnetically induced gap around the original Dirac point of the TI surface state. Although the size of gap is reported to be about 50 meV, the observable temperature of QAHE has been limited below 300 mK. We attempt magnetic-Cr modulation doping into topological insulator (Bi,Sb){sub 2}Te{sub 3} films to increase the observable temperature of QAHE. By introducing the rich-Cr-doped thin (1 nm) layers at the vicinity of both the surfaces based on non-Cr-doped (Bi,Sb){sub 2}Te{sub 3} films, we have succeeded in observing the QAHE up to 2 K. The improvement in the observable temperature achieved by this modulation-doping appears to be originating from the suppression of the disorder in the surface state interacting with the rich magnetic moments. Such a superlattice designing of the stabilized QAHE may pave a way to dissipation-less electronics based on the higher-temperature and zero magnetic-field quantum conduction.
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4] ; ;  [1] ;  [5]
  1. Department of Applied Physics and Quantum Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656 (Japan)
  2. Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)
  3. (JST), Chiyoda-ku, Tokyo 102-0075 (Japan)
  4. RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan)
  5. (CEMS), Wako 351-0198 (Japan)
Publication Date:
OSTI Identifier:
22485995
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CURRENTS; DOPED MATERIALS; FERMI LEVEL; FILMS; HALL EFFECT; LAYERS; MAGNETIC FIELDS; MAGNETIC MOMENTS; MEV RANGE 10-100; MODULATION; SUPERLATTICES; SURFACES; TITANIUM SULFIDES; TOPOLOGY