Independent Tuning of Electronic Properties and Induced Ferromagnetism in Topological Insulators with Heterostructure Approach

• DOI: 10.1021/acs.nanolett.5b01905
• Publication Date: 2015-08-19T16:09:16Z
• Authors: Zilong Jiang; Cui-Zu Chang; Chi Tang; Peng Wei; Jagadeesh S. Moodera; Jing Shi
• Keywords: Topological insulator

The quantum anomalous Hall effect (QAHE) has been recently demonstrated in Cr- and V-doped three-dimensional topological insulators (TIs) at temperatures below 100 mK. In those materials, the spins of unfilled d-electrons transition metal dopants are exchange coupled to develop a long-range ferromagnetic order, which is essential for realizing QAHE. However, addition random does not only introduce excess charge carriers that require readjusting Bi/Sb ratio, but also unavoidably introduces paramagnetic can adversely affect chiral edge transport this work, we show heterostructure approach independently tune electronic magnetic properties surface states (BixSb1-x)2Te3 without resorting doping elements. heterostructures consisting thin TI film yttrium iron garnet (YIG), high Curie temperature (~ 550 K) insulator, find contact with YIG becomes via proximity coupling revealed by (AHE). magnetized ranges from 20 150 K uncorrelated Bi fraction x (BixSb1-x)2Te3. contrast, as varied, AHE resistivity scales longitudinal resistivity. approach, decouple induced ferromagnetism TI. independent optimization provides pathway QAHE higher temperatures, important novel spintronic device applications.