Two-component anomalous Hall effect in a magnetically doped topological insulator

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• The anomalous Hall (AH) effect is crucial for understanding magnetic materials like ferromagnetic metals, semiconductors, and topological insulators (TIs).
• Previous studies have not reported the AH effect in Mn-doped Bi2Se3, a promising material for TI applications.

Purpose of the Study:

• To investigate the anomalous Hall effect in Mn-doped Bi2Se3 thin films.
• To explore the influence of Mn concentration on the AH effect and its underlying physics.

Main Methods:

• Fabrication of (Bi,Mn)2Se3 thin films.
• Measurement of the anomalous Hall effect as a function of Mn concentration and electrical gating.

Main Results:

• Observation of the anomalous Hall effect in (Bi,Mn)2Se3 thin films for the first time.
• Demonstration of a sign reversal in AH resistance with increasing Mn concentration.
• Coexistence of positive and negative AH resistances in a crossover regime.
• Tunability of the two-component AH effect and sign reversal via electrical gating in lightly doped samples.

Conclusions:

• The findings provide a basis for understanding the complex interplay between surface states, bulk states, and magnetic doping effects in TIs.
• This work sheds light on competing magnetic orders in magnetically doped TIs and the anomalous Hall effect's role.
• The tunable AH effect offers new avenues for spintronic applications utilizing magnetic TIs.