Finite-temperature dynamical correlations for the dimerized spin-1/2 chain

Article

关键词: GROUND-STATE;    HEISENBERG;    CU(NO3)2.2.5H2O;    EXCITATIONS;    SPECTRUM;   

DOI  :  10.1103/PhysRevB.98.104435

来源: SCIE

【 摘 要 】

We use the density matrix renormalization group method to compute the frequency and momentum-resolved spin-spin correlation functions of a dimerized spin-1/2 chain under a magnetic field at finite temperature. The spectral features strongly depend on the regime of the magnetic field. For increasing magnetic fields, the transitions from a gapped spin liquid phase to a Tomonaga-Luttinger liquid, and then to a totally polarized phase, can be identified in the spectra. Compared to the zero-temperature case, the finite-temperature excitations give rise to additional spectral features that we compute numerically and identify analytically as transitions from thermally excited states. We compute quantitatively the broadening of the dispersion of a single spin-flip excitation due to the temperature and find a strong asymmetric broadening. We discuss the consequences of these findings for neutron experiments on dimerized one-dimensional quantum chains.

【 授权许可】

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