Pressure-induced phase transition and bi-polaronic sliding in a hole-doped Cu_2O_3 ladder system
arXiv:cond-mat/0506334 · doi:10.1103/PhysRevB.73.094514
Abstract
We study a hole-doped two-leg ladder system including metal ions, oxygen, and electron-lattice interaction, as a model for Sr_{14-x}Ca_xCu_{24}O_{41-δ}. Single- and bi-polaronic states at 1/4-hole doping are modeled as functions of pressure by applying an unrestricted Hartree-Fock approximation to a multiband Peierls-Hubbard Hamiltonian. We find evidence for a pressure-induced phase transition between single-polaron and bi-polaron states. The electronic and phononic excitations in those states, including distinctive local lattice vibrational modes, are calculated by means of a direct-space Random Phase approximation. Finally, as a function of pressure, we identify a transition between site- and bond-centered bi-polarons, accompanied by a soft mode and a low-energy charge-sliding mode. We suggest comparisons with available experimented data.
References in corpus (10)
- Hole crystallization in the spin ladder of Sr14Cu24O41
- Static and dynamic spin correlations in the spin-glass phase of slightly-doped La_{2-x}Sr_xCuO_4
- Sliding Density-Wave in Sr_{14}Cu_{24}O_{41} Ladder Compounds
- Hole distribution for (Sr,Ca,Y,La)_14 Cu_24 O_41 ladder compounds studied by x-ray absorption spectroscopy
- Electronic States of doped spin ladders (Sr,Ca)14Cu24O41
- Topological doping and the stability of stripe phases
- Stripe structure, spectral feature and soliton gap in high Tc cuprates
- Microwave and millimeter wave spectroscopy in the slightly hole-doped ladders of SrCuO
- Local edge modes in doped cuprates with checkerboard polaronic heterogeneity
- Vibrational edge modes in intrinsically heterogeneous doped transition metal oxides