Selftrapped magnetic polaron: Exact solution of a continuum model in one dimension
Abstract
A continuum model for the selftrapped magnetic polaron is formulated and solved in one dimension using a variational technique as well as the EulerLagrange method, in the limit of J_{H}>∞, where J_{H} is the Hund'srule coupling between the itinerant electron and the localized lattice spins treated as classical spins. The EulerLagrange equations are solved numerically. The magnetic polaron state is determined by a competition between the electron kinetic energy, characterized by the hopping integral t, and the energy of the antiferromagnetic lattice, characterized by the exchange integral J. In the broadband case, i.e., for large values of α≡t/JS^{2}, the electron nucleates a saturated ferromagnetic core region (typeII polaron) similar to the Mott description, while in the opposite limit, the ferromagnetic core is only partially saturated (typeI polaron), with the crossover being at α_{c}~7.5. The magnetic polaron is found to be selftrapped for all values of α. The continuum results are also compared to the results for the discrete lattice.
 Publication:

Physical Review B
 Pub Date:
 June 2001
 DOI:
 10.1103/PhysRevB.63.214413
 Bibcode:
 2001PhRvB..63u4413P
 Keywords:

 75.25.+z;
 75.90.+w;
 Spin arrangements in magnetically ordered materials;
 Other topics in magnetic properties and materials