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arXiv · 1805.11017

Thermal Critical Points and Quantum Critical End Point in the Frustrated Bilayer Heisenberg Antiferromagnet

Jonas Stapmanns·Philippe Corboz·Frederic Mila·Andreas Honecker·Bruce Normand·Stefan Wessel
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Abstract

We consider the finite-temperature phase diagram of the $S = 1/2$ frustrated Heisenberg bilayer. Although this two-dimensional system may show magnetic order only at zero temperature, we demonstrate the presence of a line of finite-temperature critical points related to the line of first-order transitions between the dimer-singlet and -triplet regimes. We show by high-precision quantum Monte Carlo simulations, which are sign-free in the fully frustrated limit, that this critical point is in the Ising universality class. At zero temperature, the continuous transition between the ordered bilayer and the dimer-singlet state terminates on the first-order line, giving a quantum critical end point, and we use tensor-network calculations to follow the first-order discontinuities in its vicinity.

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Jonas Stapmanns, Philippe Corboz, Frederic Mila, Andreas Honecker, Bruce Normand, Stefan Wessel. 2018-09-19. Thermal Critical Points and Quantum Critical End Point in the Frustrated Bilayer Heisenberg Antiferromagnet. https://doi.org/10.1103/physrevlett.121.127201

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