2020/01/14 by Niklas Casper, Casper, Niklas, Wolfram Brenig +1
Physics and Astronomy · #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Spectroscopy and Quantum Chemical Studies #Strongly Correlated Electrons (cond-mat.str-el) #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.2001.04696
openalex publication_date 2020/01/14 · openalex created_date 2022/07/26 · openalex updated_date 2026/07/28
We present a study of the spin-1/2 Heisenberg chain with alternating ferro-\nand antiferromagnetic exchange, focusing on the role of the exchange couplings\nto cover both, dimer and Haldane limit. Employing a complementary combination\nof perturbation theory and quantum Monte Carlo simulation, we report results\nfor the magnetic susceptibility as well as the dynamic structure factor over a\nwide range of coupling constants and for different temperatures to extract the\nspin gap. For a small ferromagnetic coupling, we find good agreement between\nperturbation theory and quantum Monte Carlo. For arbitrary exchange couplings\nwe show that the dynamic structure factor, obtained from quantum Monte Carlo,\nscales between triplons and a Haldane chain spectrum. Finally, we contrast our\nfindings for the spin gap versus the exchange couplings against existing\nliterature.\n