Excitation Spectrum of Fe ^2+ in a Tetrahedral Potential: Dynamic Jahn-Teller Effect. ^*

Previous abstract Next abstract

Session Q14 - DCMP: SEMICONDUCTORS: MAGNETISM
Mixed session, Friday morning, March 24, 8:00
Room J4, San Jose Convention Center

[Q14.01] Excitation Spectrum of Fe ^2+ in a Tetrahedral Potential: Dynamic Jahn-Teller Effect. ^*

D. Colignon,E. Kartheuser (U. of Li\`ege),S. Rodriguez (Purdue U.),M. Villeret (City U., London, U. K.)

A theoretical study of the vibronic energy levels of doubly ionized iron in a tetrahedral potential of a II-VI compound will be presented. The orbital doublet and triplet states of Fe ^2+ experience energy shifts due to the spin-orbit, and spin-spin interactions and to Jahn-Teller couplings of the doublet and triplet manifolds with overtones of phonons of \Gamma_3 and \Gamma_5 symmetries, respectively. The positions of the optical absorption lines in the near and far infrared are accounted for with excellent accuracy taking the orbital splitting \Delta=2530 cm ^-1 , spin-orbit coupling \lambda=-95 cm ^-1 , spin-spin interaction \rho=0.7 cm ^-1 and Jahn-Teller interactions E_JT^(3)=2 cm ^-1 and E_JT^(5)=275 cm ^-1 describing coupling between the 3 d -electrons and phonons of energies \hbarømega_3=28 cm ^-1 and \hbarømega_5=40 cm ^-1 of symmetries \Gamma_3 and \Gamma_5 , respectively. The oscillator strengths (electric- and magnetic-dipole) are obtained for transitions within states in the orbital doublet as well as between these levels and the orbital triplet. ^* Supported in part by NSF, NATO and Fonds National de la Recherche Scientifique (Belgium).

Part Q of program listing