Field-effect Modulation of Anomalous Hall Effect in Diluted Ferromagnetic Topological Insulator Epitaxial Films

摘要

High quality chromium (Cr) doped three-dimensional topological insulator (TI)Sb2Te3 films are grown via molecular beam epitaxy on heat-treated insulatingSrTiO3(111) substrates. We report that the Dirac surface states are insensitiveto Cr doping, and a perfect robust long-range ferromagnetic order is unveiledin epitaxial Sb2-xCrxTe3 films. The anomalous Hall effect is modulated byapplying a bottom gate, contrary to the ferromagnetism in conventional dilutedmagnetic semiconductors (DMSs), here the coercivity field is not significantlychanged with decreasing carrier density. Carrier-independent ferromagnetismheralds Sb2-xCrxTe3 films as the base candidate TI material to realize thequantum anomalous Hall (QAH) effect. These results also indicate the potentialof controlling anomalous Hall voltage in future TI-based magneto-electronicsand spintronics.