Effect of Mn doping on ultrafast carrier dynamics in thin films of the topological insulator Bi2Se3

Yuri D. Glinka, Sercan Babakiray, Mikel B. Holcomb, David Lederman

Published 2015-12-22Version 1

Transient reflectivity from 12 nm thick Bi2-xMnxSe3 films revealed a strong dependence of rise-time and decay-time constants on photoexcited carrier density and Mn content. In undoped samples (x = 0), these time constants are exclusively governed by electron-electron and electron-phonon scattering, respectively, whereas in films with x = 0.013-0.27 ultrafast carrier dynamics are completely controlled by photoexcited electron trapping by ionized Mn2+ acceptors and their dimers. The shortest decay-time of ~0.75 ps measured for the film with x = 0.27 reaches the characteristic value of bilayer graphene, thus suggesting a great potential of Mn-doped Bi2Se3 films for applications in high-speed optoelectronic devices.