Dimerization Induced by the RKKY Interaction

Abstract

We report the presence of spin dimerization in the ground state of the one-dimensional Kondo lattice model at quarter filling. The emergence of this new phase of the Kondo lattice can be traced to the form of the RKKY interaction between the localized moments and provides the first example of dimerization induced indirectly by itinerant electrons. We propose this dimer ordering as the driving mechanism of the spin-Peierls phase observed in the quasi-one-dimensional organic compounds (Per)2M(mnt)(2) (M=Pt, Pd). Moreover, this suggests that a richer phase diagram than the Doniach paradigm may be needed to accommodate the physics of heavy fermion materials.

Spin Order in One-Dimensional Kondo and Hund Lattices

“…Our present calculations reproduce the results for D(i). However, the absence of a spin gap 22 and our results on the long distance spin-spin correlation functions suggest a nonspontaneously broken translation symmetry state compatible with the generalization of the LSM theorem 24 . We find that similar structures are present for other commensurate fillings n = 1/4, 1/3, 2/3 and 3/4 as well.…”

Interaction of magnetic field-dependent Peierls and spin-Peierls ground states in(Per)2[Pt(mnt)Green1, Brooks2, Kuhns3 et al. 2011Phys. Rev. B103100View full textAdd to dashboardCite

“…We note however that since EPR studies indicate an interaction between the itinerant and localized spins, an exchange interaction might be involved in the cooperative SP-CDW transition. It will be important to consider how the possibility that the Peierls transition drives the spin-Peierls transition fits in with the model of Xavier et al [9] who predict, using a single chain Kondo model, that an RKKY interaction between the localized moments is facilitated by itinerant electrons, inducing dimerization in the SP chain.…”

“…This observation suggests that the two chains are strongly coupled, even with the mismatch in q-vectors. In light of this, one [9] and two chain [10] one dimensional Kondo lattice models have been considered in treating the coupling of the itinerant electrons and localized spins associated with the onset of the T SP −CDW transition, but at present there is no complete theory that treats the two-chain (P er) 2 [P t(mnt) 2 ] case. In the work presented here, we will show that even at high magnetic fields this coupling persists, and that the initial tetramerization in the perylene chains may promote the stabilization of the SP dimerization and the resulting spin-singlet ground state.…”

Transitions from small to large Fermi momenta in a one-dimensional Kondo lattice model

“…17,18 However, indications for phases with small Fermi momentum have been shown in more recent density matrix renormalization group calculations 19 and the effects of spin dimerization in this context have been recently discussed. 20 In absence of Kondo interaction, the 1DEG and the spin chain are completely decoupled. In order to study the low-energy excitations, one can take the continuum limit so that 1DEG will be described as a Luttinger liquid.…”