Observation of Strong-Coupling Effects in a Diluted Magnetic SemiconductorGa1−xFexN

Abstract

The giant Zeeman splitting of free excitons is measured in Ga(1-x)Fe(x)N. Magneto-optical and magnetization data imply the ferromagnetic sign and a reduced magnitude of the effective p-d exchange energy governing the interaction between Fe(3+) ions and holes in GaN, N_{0}beta(app)=+0.5+/-0.2 eV. This finding corroborates the recent suggestion that the strong p-d hybridization specific to nitrides and oxides leads to significant renormalization of the valence band exchange splitting.

Fe dopant in ZnO: 2+ versus 3+ valency and ion-carrier s,p−d exchange interaction

“…The obtained N 0 β, 0.5−1 eV, is smaller than typical ironhole exchange integrals for II-VI compounds, [75][76][77][78] but of the same order as effective exchange integrals reported for wide gap DMSs 8,9,[79][80][81][82][83] With the increasing U (Fe), t 2↑ approaches the valence band (see Fig. 2), which increases the spin splitting of the VBM, and for the U (Fe)= 4 eV the N 0 β reaches 2.0 eV .…”

Upper bound for thes−dexchange integral inn-(Ga,Mn)N:Si from magnetotransport studies

“…In the case of magnetically doped wurtzite (wz) GaN, exciton magnetospectroscopy [25][26][27] and magnetic circular dichroism [28] were employed to evaluate the sp-d exchange energies in films deposited by metal-organic vapor phase epitaxy (MOVPE). These methods provide the magnitude of N 0 (β − α) rather accurately.…”

Interplay between Carrier Localization and Magnetism in Diluted Magnetic and Ferromagnetic Semiconductors

“…Furthermore, it has been suggested that a strong local potential associated with the magnetic atom can enhance the biding energy (by the so-called central cell corrections) or even produce a bound state in the gap. [22][23][24] Here, examples are Mn in ZnO and Fe in GaN, 25 which can trap a hole, despite that the corresponding donor states, Mn 2+ /Mn 3+ and Fe 3+ /Fe 4+ , respectively reside in the valence band.…”