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arXiv · 1706.06379

Magnetic signatures of quantum critical points of the ferrimagnetic mixed spin-(1/2, S) Heisenberg chains at finite temperatures

Jozef Strecka·Taras Verkholyak
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Abstract

Magnetic properties of the ferrimagnetic mixed spin-(1/2,S) Heisenberg chains are examined using quantum Monte Carlo simulations for two different quantum spin numbers S = 1 and 3/2. The calculated magnetization curves at finite temperatures are confronted with zero-temperature magnetization data obtained within density-matrix renormalization group method, which imply an existence of two quantum critical points determining a breakdown of the gapped Lieb-Mattis ferrimagnetic phase and Tomonaga-Luttinger spin-liquid phase, respectively. While a square-root behavior of the magnetization accompanying each quantum critical point is gradually smoothed upon rising temperature, the susceptibility and isothermal entropy change data provide a stronger evidence of the quantum critical points at finite temperatures through marked local maxima and minima, respectively.

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Jozef Strecka, Taras Verkholyak. 2017-06-20. Magnetic signatures of quantum critical points of the ferrimagnetic mixed spin-(1/2, S) Heisenberg chains at finite temperatures. https://doi.org/10.1007/s10909-016-1687-5

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