Excitonic polaron is directly demonstrated for the first time in InAs/GaAs quantum dots with photoluminescence method. A new peak (s′) below the ground state of exciton (s) comes out as the temperature varies from 4.2 K to 285 K, and a huge anticrossing energy of 31 meV between s′ and s is observed at 225 K, which can only be explained by the formation of excitonic polaron. The results also provide a strong evidence for the invalidity of Huang-Rhys formulism in dealing with carrier-longitudinal optical phonon interaction in quantum dot. Instead, we propose a simple two-band model, and it fits the experimental data quite well. The reason for the finding of the anticrossing is also discussed.
@article{arxiv.0708.0468,
title = {Direct observation of excitonic polaron in InAs/GaAs quantum dots},
author = {Ming Gong and Chuan-Feng Li and Geng Chen and Lixin He and F. W. Sun and Guang-Can Guo and Zhi-Chuan Niu and She-Song Huang and Yong-Hua Xiong and Hai-Qiao Ni},
journal= {arXiv preprint arXiv:0708.0468},
year = {2007}
}