Regular Article - Solid State and Materials
Spin-half Heisenberg antiferromagnet on a symmetric sawtooth chain: rotation-invariant Green’s functions and high-temperature series
Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, Svientsitskii Street 1, 79011, L’viv, Ukraine
2 Professor Ivan Vakarchuk Department for Theoretical Physics, Ivan Franko National University of L’viv, Drahomanov Street 12, 79005, L’viv, Ukraine
3 Institut für Physik, Otto-von-Guericke-Universität Magdeburg, P. O. Box 4120, 39016, Magdeburg, Germany
Accepted: 13 April 2023
Published online: 28 April 2023
We apply the rotation-invariant Green’s function method to study the finite-temperature properties of a sawtooth-chain (also called -chain) antiferromagnetic Heisenberg model at the fully frustrated point when the exchange couplings along the straight-line and zig–zag paths are equal. We also use 13 terms of high-temperature expansion series and interpolation methods to get thermodynamic quantities for this model. We check the obtained predictions for observable quantities by comparison with numerics for finite systems. Although our work refers to a one-dimensional case, the utilized methods work in higher dimensions too and are applicable for examining other frustrated quantum spin lattice systems at finite temperatures.
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