Near band-gap photoluminescence and reflectivity in magnetic field are employed to determine the exchange-induced splitting of free exciton states in paramagnetic wurtzite Ga1-xMnxN, x < 1%, grown on sapphire substrates by metal-organic vapor phase epitaxy. The band gap is found to increase with x. The giant Zeeman splitting of all three excitons A, B and C is resolved, enabling the determination of the apparent exchange integrals N0alpha(app) = 0.0 +/- 0.1 eV and N0beta(app) = +0.8 +/- 0.2 eV. These non-standard values and signs of the s - d and p - d exchange energies are explained in terms of recent theories that suggest a contribution of the electron-hole exchange to the spin splitting of the conduction band and a renormalization of the free hole spin-splitting by a large p - d hybridization. According to these models, in the limit of a strong p - d coupling, the band gap of (Ga,Mn)N increases with x and the order of hole spin subbands is reversed, as observed.
Biexcitons in Ruddlesden-Popper Metal Halides Probed by Nonlinear Coherent Spectroscopy
Department of Physics and Center for Functional Materials, Wake Forest University（维克森林大学物理系与功能材料中心）；Institut Courtois, Université de Montréal（蒙特利尔大学库尔托瓦研究所）
Spin dynamics of excitons and carriers in mixed-cation MA$_{x}$FA$_{1-x}$PbI$_{3}$ perovskite crystals: alloy fluctuations probed by optical orientation
Empa-Swiss Federal Laboratories for Materials Science and Technology（瑞士联邦材料科技研究所）
Optical-phonon mediated exciton energy relaxation with highly preserved spin states Optical-phonon mediated exciton energy relaxation with highly preserved spin states in a single quantum dot
