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Spin excitations and magnon fractionalization in a quantum spin ladder

Christian Rüegg

Bulletin of the American Physical SocietyMar 16, 20100 citations

Spin liquid fingerprints in the thermal transport of a Kitaev-Heisenberg ladder

Alexandros Metavitsiadis, Christina Psaroudaki, Wolfram Brenig

We identify fingerprints of a proximate quantum spin liquid (QSL), observable by finite-temperature dynamical thermal transport within a minimal version of the idealized Kitaev model on a two-leg ladder if subjected to inevitably present Heisenberg couplings. Using exact diagonalization and quantum typicality, we uncover (i) an insulator-conductor crossover induced by recombination of fractionalized excitations at small Heisenberg couplings, (ii) low- and high-energy signatures of fractionalized excitations, which survive far off the pure QSL point, and (iii) a nonmonotonous current lifetime versus Heisenberg couplings. Guided by perturbation theory, we find (iv) a Kitaev-exchange-induced ``one-magnon'' contribution to the dynamical heat transport in the strong Heisenberg rung limit.We identify fingerprints of a proximate quantum spin liquid (QSL), observable by finite-temperature dynamical thermal transport within a minimal version of the idealized Kitaev model on a two-leg ladder if subjected to inevitably present Heisenberg couplings. Using exact diagonalization and quantum typicality, we uncover (i) an insulator-conductor crossover induced by recombination of fractionalized excitations at small Heisenberg couplings, (ii) low- and high-energy signatures of fractionalized excitations, which survive far off the pure QSL point, and (iii) a nonmonotonous current lifetime versus Heisenberg couplings. Guided by perturbation theory, we find (iv) a Kitaev-exchange-induced ``one-magnon'' contribution to the dynamical heat transport in the strong Heisenberg rung limit.

arXiv:1806.02344Physical review. B./Physical review. BMay 17, 20198 citations

Excitations in a perfect magnetized quantum spin ladder

A. Zheludev, D. Schmidiger, S. Mühlbauer +7 more

Bulletin of the American Physical SocietyMar 19, 20130 citations

Low-Temperature Dynamics of Magnons in a Spin- 1 / 2 Ladder Compound

Bálint Náfrádi, T. Keller, Hirotaka Manaka +2 more

We have used a combination of neutron resonant spin-echo and triple-axis spectroscopies to determine the energy, fine structure, and linewidth of the magnon resonance in the model spin-1/2 ladder antiferromagnet IPA-CuCl(3) at temperatures T≪Δ(0)/k(B), where Δ(0) is the spin gap at T=0. In this low-temperature regime we find that the results deviate substantially from the predictions of the nonlinear sigma model proposed as a description of magnon excitations in one-dimensional quantum magnets and attribute these deviations to real-space and spin-space anisotropies in the spin Hamiltonian as well as scattering of magnon excitations from a dilute density of impurities. These effects are generic to experimental realizations of one-dimensional quantum magnets.We have used a combination of neutron resonant spin-echo and triple-axis spectroscopies to determine the energy, fine structure, and linewidth of the magnon resonance in the model spin-1/2 ladder antiferromagnet IPA-CuCl(3) at temperatures T≪Δ(0)/k(B), where Δ(0) is the spin gap at T=0. In this low-temperature regime we find that the results deviate substantially from the predictions of the nonlinear sigma model proposed as a description of magnon excitations in one-dimensional quantum magnets and attribute these deviations to real-space and spin-space anisotropies in the spin Hamiltonian as well as scattering of magnon excitations from a dilute density of impurities. These effects are generic to experimental realizations of one-dimensional quantum magnets.

arXiv:1102.0214Physical Review LettersApr 25, 201125 citations

Quantum spin ladder with dynamic phonons: Bound states of magnons and phonons

Oleg P. Sushkov

We consider the two-chain Heisenberg ladder with antiferromagnetic interactions. Our approach is based on the description of spin excitations as triplets above a strong-coupling singlet ground state. It is shown that interaction with dynamic phonons drastically changes the dispersion of the elementary triplet excitation (magnon) and the spin structure factor. It is also shown that a different triplet excitation appears in the spectrum: the bound state of a magnon and a phonon.

arXiv:cond-mat/9905030Physical review. B, Condensed matterDec 1, 19994 citations

Profiles of magnons and spinons in a spin ladder

David Robinson Clarke, Oleg Tchernyshyov, J.-B. Fouet +1 more

Bulletin of the American Physical SocietyMar 13, 20060 citations

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