Quasiparticle Self-Consistent <i>GW</i> Analysis of Excited States and Model Construction of 3<i>d</i>² Luminescent Centers in α-Aluminum Oxide

Abstract

Cr 4+ -doped crystals are promising materials for infrared solid laser applications. In order to choose proper host materials of Cr 4+ from the wide variety of crystals, multiplet energy levels of Cr 4+ should be evaluated without experimental information. A newly developed firstprinciples method for determining the mean-field Hamiltonian of the localized luminescent center based on quasiparticle self-consistent GW was applied to 3d 2 transition metal ions (Cr 4+ and V 3+ ) in ¡-Al 2 O 3 . Our method gave good agreement with the effective Coulomb parameters and crystal-field parameters estimated from experimental data. Multiplet energy structures were therefore well reproduced by our method. These results show the possibility of designing new laser host materials within the framework of the first-principles calculations.

Pressure-dependent multiplet-excitation energies of α-Al2O3:Cr3+ by the first-principles method

“…Recently, we developed a new method to determrine the model Hamiltonian [11][12][13] based on the quasiparticle selfconsistent GW (QSGW) method. The QSGW method is a first-principles method which can determine the one-body Hamiltonian describing the independent particle picture very well.…”

“…In Ref. 12,13) In this paper, we treat pressure dependence of the multiplet energies of α-Al 2 O 3 :Cr 3+ . α-Al 2 O 3 :Cr 3+ is a well-known red gemstone, a ruby, which is used for the first laser by Maiman.…”