Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 32: Correlated Electrons - Low-dimensional Materials II

TT 32.9: Vortrag

Dienstag, 8. März 2005, 18:15–18:30, TU H2053

Strong Coulomb effects in hole-doped Heisenberg chains — •Jürgen Schnack — Universität Osnabrück, Fachbereich Physik, D-49069 Osnabrück, Germany

Substances like the “telephone number compound” Sr₁₄Cu₂₄O₄₁ are intrinsically hole-doped. The involved interplay of spin and charge dynamics is a challenge for theory. In this Letter we propose to describe hole-doped Heisenberg spin rings by means of complete numerical diagonalization of a Heisenberg Hamiltonian that depends parametrically on hole positions and includes the screened Coulomb interaction among the holes. It is demonstrated that key observables like magnetic susceptibility, specific heat, and inelastic neutron scattering cross section depend sensitively on the dielectric constant of the screened Coulomb potential which opens the fascinating possibility to determine the in-medium dielectric constant experimentally from such observables [1,2].

[1] J. Schnack, Phys. Rev. Lett., submitted, cond-mat/0409650

[2] J. Schnack, F. Ouchni, J. Magn. Magn. Mater. (2004) accepted, cond-mat/0406592