Physics – Condensed Matter – Materials Science
Scientific paper
2010-08-10
Phys. Rev. B, 82, 144426 (2010)
Physics
Condensed Matter
Materials Science
Scientific paper
10.1103/PhysRevB.82.144426
We derive and investigate the microscopic model of the quantum magnet BiCu2PO6 using band structure calculations, magnetic susceptibility and high-field magnetization measurements, as well as ED and DMRG techniques. The resulting quasi-one-dimensional spin model is a two-leg AFM ladder with frustrating next-nearest-neighbor couplings along the legs. The individual couplings are estimated from band structure calculations and by fitting the magnetic susceptibility with theoretical predictions, obtained using ED. The nearest-neighbor leg coupling J1, the rung coupling J4, and one of the next-nearest-neighbor couplings J2 amount to 120-150 K, while the second next-nearest-neighbor coupling is J2'~J2/2. The spin ladders do not match the structural chains, and although the next-nearest-neighbor interactions J2 and J2' have very similar superexchange pathways, they differ substantially in magnitude due to a tiny difference in the O-O distances and in the arrangement of non-magnetic PO4 tetrahedra. An extensive ED study of the proposed model provides the low-energy excitation spectrum and shows that the system is in the strong rung coupling regime. The strong frustration by the next-nearest-neighbor couplings leads to a triplon branch with an incommensurate minimum. This is further corroborated by a strong-coupling expansion up to second order in the inter-rung coupling. Based on high-field magnetization measurements, we estimate the spin gap of 32 K and suggest the likely presence of antisymmetric DM anisotropy and inter-ladder coupling J3. We also provide a tentative description of the physics of BiCu2PO6 in magnetic field, in the light of the low-energy excitation spectra and numerical calculations based on ED and DMRG. In particular, we raise the possibility for a rich interplay between one- and two-component Luttinger liquid phases and a magnetization plateau at 1/2 of the saturation value.
Geibel Christoph
Janson Oleg
Kasinathan Deepa
Läuchli Andreas M.
Nath Ramesh
No associations
LandOfFree
Bridging frustrated-spin-chain and spin-ladder physics: quasi-one-dimensional magnetism of BiCu2PO6 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Bridging frustrated-spin-chain and spin-ladder physics: quasi-one-dimensional magnetism of BiCu2PO6, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bridging frustrated-spin-chain and spin-ladder physics: quasi-one-dimensional magnetism of BiCu2PO6 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-584497