129 citations · 1k across the 26 of their papers we have counts for
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Jordan-Wigner approach to dynamic correlations in spin-ladders
Tamara S. Nunner, Thilo Kopp
We present a method for studying the excitations of low-dimensional quantum spin systems based on the Jordan-Wigner transformation. Using an extended RPA-scheme we calculate the co…
Cyclic Spin Exchange in Cuprate Spin Ladders
Tamara S. Nunner, Philipp Brune, Thilo Kopp +2
We investigate the influence of a cyclic spin exchange J_{cyc} on the one- and two-triplet excitations of an undoped two-leg S=1/2 ladder, using the density matrix renormalization…
Magnetic excitations in two-leg spin 1/2 ladders: experiment and theory
M. Grueninger, M. Windt, T. Nunner +8
Magnetic excitations in two-leg S=1/2 ladders are studied both experimentally and theoretically. Experimentally, we report on the reflectivity, the transmission and the optical con…
Optical spectroscopy of (La,Ca)14Cu24O41 spin ladders: comparison of experiment and theory
M. Grueninger, M. Windt, T. Nunner +8
Transmission and reflectivity of La_x Ca_14-x Cu_24 O_41 two-leg spin-1/2 ladders were measured in the mid-infrared regime between 500 and 12000 1/cm. This allows us to determine t…
Observation of two-magnon bound states in the two-leg ladders of (Ca,La)14Cu24O41
M. Windt, M. Grueninger, T. Nunner +8
Phonon-assisted 2-magnon absorption is studied at T=4 K in the spin-1/2 two-leg ladders of Ca_14-x La_x Cu_24 O_41 (x=5 and 4) for polarization of the electrical field parallel to…
Imperfect nesting and Peierls instability for a two-dimensional tight-binding model
Qingshan Yuan, Tamara Nunner, Thilo Kopp
Based on a half-filled two-dimensional tight-binding model with nearest-neighbour and next nearest-neighbour hopping the effect of imperfect Fermi surface nesting on the Peierls in…
Mid-infrared absorption in YBa2Cu3O6: Failure of spin-wave theory in undoped cuprates?
M. Grueninger, D. van der Marel, A. Damascelli +4
The optical conductivity sigma (omega) of undoped YBa2Cu3O6 is studied in detail in the mid-infrared range. Substitutions on all but the Ba site are used to identify the prominent…