Field-Dependent Specific Heat and Energy Gap in the Yb4As3 Compound |
| R. Matysiak
Institute of Engineering and Computer Education, University of Zielona Góra, Prof. Z. Szafrana 4, 65-516 Zielona Góra, Poland |
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| We report the low-temperature specific-heat simulation results and reanalyzed measurement data on polydomain Yb4As3 in magnetic fields B = 0 and 6 T. The data considered here are independent and supplement those considered earlier. A quantitative agreement has again been achieved between the magnetic experimental specific-heat data and the numerical results obtained by the quantum transfer-matrix simulation technique, yielding a new evidence in favour of the Heisenberg model of the antiferromagnetic spin S = 1/2 chain with the value of the exchange integral J/kB = - 28 K. The finite-size quantum transfer matrix approximants have been extrapolated exploiting the procedure developed previously. On the basis of the data in magnetic field and using the corresponding density-matrix renormalization group results, the energy-gap size Δp has been estimated for the applied magnetic field B = 6 T, leading to the experimental verification in the extended region of the scaling law Δp ∿ B2/3 following from the sine-Gordon model. |
| DOI: 10.12693/APhysPolA.118.969 PACS numbers: 75.10.Jm, 75.40.Cx, 75.40.Mg, 71.55.Ak |