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arXiv · 2012.00449

Fermion enhanced first-order phase transition and chiral Gross-Neveu tricritical point

Yuzhi Liu·Zi Yang Meng·Shuai Yin
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Abstract

The fluctuations of massless Dirac fermion can not only turn a first-order bosonic phase transition (in the Landau sense) to a quantum critical point, but also work reversely to enhance the first-order transition itself, depending on the implementation of finite size effects in the coupling corrections. Here, we report a case study of the latter by employing quantum Monte Carlo simulation upon a lattice model in which the bosonic part featuring the Landau-Devonshire first-order phase transition and Yukawa coupled to the Dirac fermions. We find that the parameter range for the first-order phase transition becomes larger as the Yukawa coupling increases and the microscopic mechanism of this phenomena is revealed, at a quantitative level, as the interplay between the critical fluctuations and the finite-size effects. Moreover, the scaling behavior at the separation point between the first-order and the continuous phase transitions is found to belong to the chiral tricritical Gross-Neveu universality. Our result demonstrates that the interplay of massless Dirac fermions, critical fluctuations and the finite size effects could trigger a plethora of interesting phenomena and therefore great care is called for when making generalizations.

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Yuzhi Liu, Zi Yang Meng, Shuai Yin. 2021-02-27. Fermion enhanced first-order phase transition and chiral Gross-Neveu tricritical point. https://doi.org/10.1103/physrevb.103.075147

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