6 papers
Quantum Spin Systems: From Spin Gaps to Pseudo Gaps
P. Lemmens, M. Fischer, M. Grove +5
Many low dimensional spin systems with a dimerized or ladder-like antiferromagnetic exchange coupling have a gapped excitation spectrum with magnetic bound states within the spin g…
Spin gap behavior and charge ordering in α^{\prime}-NaV_2O_5 probed by light scattering
M. Fischer, P. Lemmens, G. Els +5
We present a detailed analysis of light scattering experiments performed on the quarter-filled spin ladder compound -NaVO for the temperature range 5 KT$…
Magnetic bound states in the quarter-filled ladder system }
P. Lemmens, M. Fischer, G. Els +6
Raman scattering in the quarter-filled spin ladder system alpha'-NaV_2O_5 shows in the dimerized singlet ground state () an unexpected sequence of three magnetic…
Magnetic Bound States in Dimerized Quantum Spin Systems
P. Lemmens, M. Fischer, M. Grove +5
Magnetic bound states are a general phenomenon in low dimensional antiferromagnets with gapped singlet states. Using Raman scattering on three compounds as dedicated examples we sh…
Dopant-Bound Spinons in Cu_(1-x)Zn_xGeO_3
G. Els, G. S. Uhrig, P. Lemmens +7
Polarized inelastic light scattering experiments on Cu_(1-x)Zn_xGeO_3 (0<= x <= 0.045) single crystals show for x<>0 a new distinct mode at nearly half the energy of the singlet re…
Observation of three-magnon light scattering in CuGeO_3
G. Els, P. H. M. van Loosdrecht, P. Lemmens +7
Temperature and magnetic field dependent polarized Brillouin spectra of CuGeO_3 are reported. In addition to a bound singlet state at 30 cm^{-1}, a new feature has been observed at…