Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 38: Correlated Electrons: Low-dimensional Systems - Models 1
TT 38.4: Vortrag
Donnerstag, 26. März 2009, 10:15–10:30, HSZ 301
Local density of states of 1D Mott insulators and CDW states with a boundary — •Dirk Schuricht1, Fabian H. L. Essler1, Akbar Jaefari2, and Eduardo Fradkin2 — 1The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, UK — 2Department of Physics, University of Illinois at Urbana-Champaign, USA
We determine the local density of states (LDOS) of one-dimensional incommensurate charge density wave (CDW) states in the presence of a strong impurity potential, which is modeled by a boundary[1]. We find that the CDW gets pinned at the impurity, which results in a singularity in the Fourier transform of the LDOS at momentum 2kF. At energies above the spin gap we observe dispersing features associated with the spin and charge degrees of freedom respectively. In the presence of an impurity magnetic field we observe the formation of a bound state localized at the impurity. All of our results carry over to the case of 1D Mott insulators by exchanging the roles of spin and charge degrees of freedom. We discuss the implications of our result for scanning tunneling microscopy experiments on spin-gap systems such as two-leg ladder cuprates.
[1] D. Schuricht, F. H. L. Essler, A. Jeafari, and E. Fradkin, Phys. Rev. Lett. 101, 086403 (2008).