Adiabatic Method for Excitonic Molecules

Abstract

The binding energy for excitonic molecules, four-body systems with Coulomb interaction, is investigated using the adiabat,ic method usually applied to three-body Coulomb systems. The infinite system of coupled Schrodinger-type equations obtained, is approximated by a finite system of twenty-one coupled equations and solved. The investigation gives an increase in binding of these systems practically in the whole region 0 < CT = me/mh 5 1, compared to previous variational results.Die Bindungsenergie fur Exzitonenmolekule, Vierkorpersysteme mit Coulomb-Wechselwirkung, wird mit der adiabatischen Methode untersucht, die gewohnlich fur Drei-Korper-Coulombsysteme benutzt wird. Das erhaltene unendliche System gekoppelter Gleichungen vom Schriidingertyp wird durch ein endliches System von einundzwanzig gekoppelten Gleichungen genahert und gelost. Die Untersuchung ergibt ein Anwachsen der Bindnng dieses Systems praktisch im gesamten Bereich 0 < u = me/mh 5 1, verglichen zu friiheren Variationsergebnissen.

Spin‐Phonon Interaction beyond the Limit of Spin‐wave Approximation

“…Our expression (5) obtained beyond the limits of the spin-wave approximation differs from the one obtained in this approximation by the fact, that instead of the number of magnons as in [7] we have the respective spin correlation function.…”

“…The expression (5) is more complete than the one given in the paper [4], since there the spin correlation functions were absent. Returning to the spin wave approximation we replace here Nk+,f is the number of magnons and get the previously obtained result [ 7 ] .…”

“…The expression for A E ( k ) in [7] was applied to calculate the temperature dependence of the spontaneous magnetization in the low temperature region [3]. I n the present paper we evaluate T(k) in this temperature region.…”