Origin of coherent phonons in Bi2Te3 excited by ultrafast laser pulses

Author

• Yaguo Wang, Birck Nanotechnology Center, Purdue UniversityFollow
• Liang Guo, Birck Nanotechnology Center, Purdue UniversityFollow
• Xianfan Xu, Birck Nanotechnology Center, Purdue UniversityFollow
• Jonathan Pierce, RTI Int.
• Rama Venkatasubramanian, Johns Hopkins University

Abstract

Femtosecond laser pulses are used to excite coherent optical phonons in single crystal Bi2Te3 thin films. Oscillations from low-and high-frequency A(1g) phonon modes are observed. A perturbation model based on molecular dynamics reveals various possibilities of phonon generation due to complex interactions among different phonon modes. In order to elucidate the process of phonon generation, measurements on thin films with thicknesses below the optical absorption depth are carried out, showing that a gradient force is necessary to excite the observed A(1g) phonon modes, which provides a refined picture of displacive excitation of coherent phonon.

Comments

First published in the Physical Review B and is available online at: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.88.064307

Keywords

DISPLACIVE EXCITATION; SB2TE3; MECHANISM; SURFACE; BI2SE3; RAMAN; SB

DOI

10.1103/PhysRevB.88.064307

Citation

Wang, Yaguo; Guo, Liang; Xu, Xianfan; Pierce, Jonathan; and Venkatasubramanian, Rama, "Origin of coherent phonons in Bi2Te3 excited by ultrafast laser pulses" (2013).

Date of this Version

8-26-2013

Recommended Citation

Wang, Yaguo; Guo, Liang; Xu, Xianfan; Pierce, Jonathan; and Venkatasubramanian, Rama, "Origin of coherent phonons in Bi2Te3 excited by ultrafast laser pulses" (2013). Birck and NCN Publications. Paper 1451.
http://dx.doi.org/10.1103/PhysRevB.88.064307