0000000000280395
AUTHOR
J. Sabczynski
Polarons in thet-J model
A convenient form of the Peierls-Hubbard Hamiltonian is obtained for the case when the Hubbard repulsion is the largest energy parameter. It allows to consider in the spin-wave approximation the properties of the one-hole low-lying excitations of a 2d lattice. For the parameters approximately corresponding to La2CuO4 it is shown that the hole polarons in the CuO2 planes of lightly doped samples are of large size with a solitonlike-shaped highly asymmetric wave function oriented along the diagonals of the planes or of small size depending on the value of the electron-phonon coupling. In both cases the cooperative effect of the electron-phonon and electron-magnon interactions leads to a large…
Energy spectrum and transport properties of the two-dimensional t-J model
Abstract The formation of a ferromagnetically ordered region around a hole in the two-dimensional t-J model is investigated. The energy bands characterized by different values of the z-component of the total spin are analysed. A strong anisotropy of the lower-energy bands is found. For intermediate coupling of additionally included optical phonons, this anisotropy leads to a large polaronic state with an anisotropic envelope oriented along the plane diagonals. In the strong-coupling case the competition between the hole-magnon and the hole-phonon interactions prevents the formation of ferrons. Owing to the large effective mass in both cases, the hole transport takes place via hopping, with …
Dissipation of vibronic energy in a dimer
Abstract The density matrix theory is used for the study of the dissipative quantum dynamics of electron transfer in a dimer. The vibrational modes of the dimer are divided into a single interaction coordinate coupling to the transfered electron and the remaining modes which form a dissipative environment. To correlate the dissipative dynamics with the exact eigenlevels computed for the model system without dissipative environment we analyse the time dependence of the expectation value of the number of vibrational quanta. We analyse the renormalisation of the eigenvalues due to the damping and the relaxation of an excitation into these states.