Enhancement of topological surface states induced by magnetic element Dy in Bi2Te3 films

Magnetic element doping often significantly affects the surface states of topological insulators with broken time-reversal symmetry. Here, we systematically investigate the effects of magnetic rare-earth Dy doping on the structural and electronic properties of Bi 2 Te 3 polycrystalline films synthesized by chemical vapor deposition (CVD). The crystal structure of Bi 2 Te 3 phase can remain intact even when the Dy dopant concentration is as high as 18.9 at.%. Structural analysis reveals that Dy incorporation induces lattice distortions and defect formation, leading to significant disorder and suppressed bulk carrier density. Temperature-dependent resistivity measurements demonstrate a transition from metallic to semiconducting behavior upon Dy doping, indicating bulk carrier localization. Magnetoresistance studies highlight the emergence of weak antilocalization (WAL) at low magnetic fields and non-saturating linear magnetoresistance (LMR) at high fields, signifying the dominance of topological surface states in electronic transport. These findings provide key insights for engineering quantum coherent devices based on magnetic element doped topological insulators.