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

Journal Article · Mon Nov 02 04:00:00 EST 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4935075· OSTI ID:22485995

Yoshimi, R.; Yasuda, K.; Kozuka, Y. ^[1]; Tsukazaki, A. ^[2]; Takahashi, K. S. ^[3]; Kawasaki, M.; Tokura, Y. ^[1]

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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. RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan)

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.

• OSTI ID: 22485995
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 18 Vol. 107; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

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