A ug 1 99 5 Phenomenolgical model of elastic distortions near the spin - Peierls transition in CuGeO
نویسنده
چکیده
A phenomenological model of the Landau type forms the basis for a study of elastic distortions near the spin-Peierls transition T c in CuGeO 3. The atomic displacements proposed by Hirota et al. are accounted for by the model which includes linear coupling between Cu and O distortions. Cu displacements are seen to be responsible for anomalies in the elastic properties at T c , whereas incipient O distortions give rise to temperature dependence below T c. A discussion of possible critical behavior is also made.
منابع مشابه
0 D ec 1 99 6 Magnetic interactions and the pressure phase - diagram of CuGeO
Magnetic interactions and the pressure phase-diagram of CuGeO 3. Abstract A pressure and temperature dependent Raman study of the vibrational and spin dynamics in CuGeO 3 is presented. A new low temperature, high pressure phase has been identified, and a pressure-temperature phase-diagram is proposed for CuGeO 3. The pressure dependence of the effective exchange interaction , of the spin-Peierl...
متن کاملar X iv : c on d - m at / 9 80 60 22 v 1 2 J un 1 99 8 Lattice Dimerization in the Spin - Peierls Compound CuGeO 3
The uniaxial pressure dependences of the exchange coupling and the structural distortion in the dimerized phase of CuGeO3 are analyzed. A minimum magnetic dimerization of 3 % is obtained, incompatible with an adiabatic approach to the spin–Peierls transition. Exploring the properties of an Heisenberg spin chain with dynamical spin-phonon coupling, the dimerization dependence of the spin excitat...
متن کاملD ec 1 99 6 Magnetic interactions and the pressure phase - diagram of CuGeO
Magnetic interactions and the pressure phase-diagram of CuGeO 3. Abstract A pressure and temperature dependent Raman study of the vibrational and spin dynamics in CuGeO 3 is presented. A new low temperature, high pressure phase has been identified, and a pressure-temperature phase-diagram is proposed for CuGeO 3. The pressure dependence of the effective exchange interaction , of the spin-Peierl...
متن کامل0 Superexchange and lattice distortions in the spin – Peierls system
We present a study of the nearest–neighbor (nn) and next–nearest–neighbor (nnn) exchange constants between magnetic Cu centers of the spin–Peierls material CuGeO 3. The dependence of these constants on the lattice parameters (modified e.g. by variation of temperature, pressure or doping) is calculated. Based on the observation that the bond angles are more susceptible than the bond lengths we p...
متن کاملElectronic Properties of α ′ - NaV 2 O 5
1 General properties of α −NaV 2 O 5 and motivation for a spectroscopic study Introduction – α −NaV 2 O 5 is one of the several phases in the class of Na x V 2 O 5 systems [1] and until now it is by far the most studied of them. Since 1996 this compound (denoted in the following simply by NaV 2 O 5) has received considerable attention because it was thought to be the second realization, after C...
متن کامل