Ferromagnetism and spin waves in diluted magnetic semiconductors

✍ Scribed by Jürgen König; Hsiu-Hau Lin; Allan H MacDonald

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 103 KB
• Volume: 10
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(01)00069-8

✦ Synopsis

We present a theory of carrier-induced ferromagnetism in diluted magnetic semiconductors (III,Mn)V which allows for arbitrary itinerant-carrier spin polarization and dynamic correlations. Both ingredients, which are absent in an RKKY description, are essential in identifying the system's elementary excitations and describing their properties. We ÿnd a branch of gapped collective modes, in addition to the spin waves and Stoner continuum which occur in metallic ferromagnets. We determine the low-temperature spin sti ness and derive, in di erent regimes, its dependence on the exchange coupling between magnetic ions and free carriers, as well as on the e ective band mass.