Experimental investigation of polaron effects in Ga1xMnxAs by time-resolved and continuous-wave midinfrared spectroscopy

E. Kojima, J. B. Héroux, R. Shimano, Y. Hashimoto, S. Katsumoto, Y. Iye, and M. Kuwata-Gonokami
Phys. Rev. B 76, 195323 – Published 21 November 2007

Abstract

The magneto-optical properties of a 1μm-thick Ga0.94Mn0.06As sample having a 110K Curie temperature are investigated by time-resolved pump-probe and continuous-wave (cw) midinfrared transmittance spectroscopies. The pump pulses are linearly polarized and have a 3.1eV energy, a 130fs width, and a 660μJcm2 fluence. They produce a thermally driven demagnetization process in the hundreds of picosecond time scale. A three-temperature model based on one-dimensional diffusion equations was developed to compute the carrier, lattice, and spin temperatures in the material. We observed that an average photoinduced spin temperature increase near 3K leads to an augmentation of the Mn acceptor impurity binding energy in the range of 1meV. cw absorption measurements were performed at temperatures ranging from 4to300K, and a nonmonotonic temperature dependence of the position of the midinfrared absorption peak is found that is consistent with the increased binding energy observed by time-resolved measurements. The variation of the sample resistivity with temperature is phenomenologically related to the optical measurements. Results are compatible with a polaron percolation model of ferromagnetism.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
2 More
  • Received 10 May 2007

DOI:https://doi.org/10.1103/PhysRevB.76.195323

©2007 American Physical Society

Authors & Affiliations

E. Kojima1, J. B. Héroux1, R. Shimano1,*, Y. Hashimoto2, S. Katsumoto2, Y. Iye2, and M. Kuwata-Gonokami1,†

  • 1Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan and SORST-CREST, Japan Science and Technology Agency (JST), 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
  • 2Institute for Solid State Physics, The University of Tokyo, 6-3-7 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan

  • *Present address: Department of Physics, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
  • Corresponding author: gonokami@ap.t.u-tokyo.ac.jp

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 76, Iss. 19 — 15 November 2007

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×