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Crossover between weak antilocalization and weak localization in a magnetically doped topological insulator
Minhao Liu1, Jinsong Zhang, Cui-Zu Chang
1State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China.
Physical Review Letters
|March 10, 2012
Summary
Magnetically doped Bi(2)Se(3) topological insulator films show tunable quantum transport. Doping with magnetic impurities drives a crossover from topological insulator to trivial semiconductor, altering electron localization.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Transport Phenomena
Background:
- Topological insulators (TIs) possess unique electronic properties due to spin-orbit interactions.
- Understanding and controlling quantum transport in ultrathin TI films is crucial for spintronic applications.
- Magnetic doping offers a route to break time-reversal symmetry and modify TI electronic states.
Purpose of the Study:
- To investigate the magnetotransport properties of magnetically doped Bi(2)Se(3) topological insulator ultrathin films.
- To explore the influence of magnetic impurity concentration on quantum transport phenomena.
- To understand the mechanism behind the observed crossover in localization behavior.
Main Methods:
- Growth of Bi(2)Se(3) topological insulator ultrathin films using molecular beam epitaxy.
- Magnetotransport measurements were conducted under varying magnetic impurity concentrations, temperatures, and magnetic fields.
- Analysis of the crossover between weak antilocalization and weak localization regimes.
Main Results:
- A systematic crossover from weak antilocalization to weak localization was observed with changing magnetic impurity concentration, temperature, and magnetic field.
- The localization properties were found to be strongly correlated with the sample's magnetization.
- Evidence suggests a transformation of the material from a topological insulator to a dilute magnetic semiconductor.
Conclusions:
- Magnetic impurities effectively tune the quantum transport properties of Bi(2)Se(3) topological insulators.
- Breaking time-reversal symmetry through magnetic doping induces a topological phase transition.
- This provides an effective strategy for manipulating quantum transport in topological materials.
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