Iaizzi, AdamDamle, KedarSandvik, Anders W.2018-11-272018-11-272018-08-06Adam Iaizzi, Kedar Damle, Anders W Sandvik. 2018. "Metamagnetism and zero-scale-factor universality in the two-dimensional J - Q model." Physical Review B, Volume 98, Issue 6. https://doi.org/10.1103/PhysRevB.98.0644052469-99502469-9969https://hdl.handle.net/2144/32713Using a combination of quantum Monte Carlo and exact methods, we study the field-driven saturation transition of the two-dimensional J − Q model, in which the antiferromagnetic Heisenberg exchange ( J ) coupling competes with an additional four-spin interaction ( Q ) that favors valence-bond solid order. For small values of Q , the saturation transition is continuous and is expected to be governed by zero-scale-factor universality at its upper critical dimension, with a specific form of logarithmic corrections to scaling (first proposed by Sachdev et al. [Phys. Rev. B 50, 258 (1994)]). Our results conform to this expectation, but the logarithmic corrections to scaling do not match the form predicted by Sachdev et al. We also show that the saturation transition becomes first order above a critical coupling ratio ( Q / J ) min and is accompanied by magnetization jumps—metamagnetism. We obtain an exact solution for ( Q / J ) min using a high magnetization expansion, and confirm the existence of the magnetization jumps beyond this value of coupling using quantum Monte Carlo simulations.Materials sciencePhysics, appliedPhysics, condensed matterPhysicsQuantum antiferromagnetsSimulationsArticle10.1103/PhysRevB.98.0644050000-0002-5638-4619 (Sandvik, Anders W)