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

Abstract

Transient reflectivity (TR) measured at laser photon energy 1.51 eV from the indirectly intersurface coupled topological insulator Bi2-xMnxSe3 films (12 nm thick) revealed a strong dependence of the rise-time and initial 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 (~0.75 ps) measured for the film with x = 0.27 suggests a great potential of Mn-doped Bi2Se3 films for applications in high-speed optoelectronic devices. Using Raman spectroscopy exploiting similar laser photon energy (1.58 eV), we demonstrate that due to indirect intersurface coupling in the films, the photoexcited electron trapping in the bulk enhances the electron-phonon interaction strength in Dirac surface states.

References in corpus (10)

• Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase
• Ultrafast Optical Excitation of a Persistent Surface-State Population in the Topological Insulator Bi2Se3
• Ultrafast carrier and phonon dynamics in Bi2Se3 crystals
• Spatially resolved femtosecond pump-probe study of topological insulator Bi2Se3
• Gigantic surface life-time of an intrinsic topological insulator revealed via time-resolved (pump-probe) ARPES
• Effect of carrier recombination on ultrafast carrier dynamics in thin films of the topological insulator Bi2Se3
• Acoustic phonon dynamics in thin-films of the topological insulator Bi2Se3
• Resonance-type thickness dependence of optical second harmonic generation in thin-films of the topological insulator Bi2Se3
• Thickness tunable quantum interference between surface phonon and Dirac plasmon states in thin-films of the topological insulator Bi2Se3
• Plasmon-enhanced electron-phonon coupling in Dirac surface states of the thin-film topological insulator Bi2Se3

Cited by in corpus (4)

• Nonlinear Optical Observation of Coherent Acoustic Dirac Plasmons in Thin-Film Topological Insulators
• Suppression of transport spin-polarization of surface states with emergence of ferromagnetism in Mn-doped Bi2Se3
• Comment on 'Unraveling Photoinduced Spin Dynamics in the Topological Insulator Bi2Se3'
• Research on topological materials using ultrafast spectroscopy