Ground-state phases of $S = 1/2$ Heisenberg models on the body-centered cubic lattice

Rajah P. Nutakki; Filippo Vicentini

paper

Ground-state phases of $S = 1/2$ Heisenberg models on the body-centered cubic lattice

arXiv:2602.10008

Abstract

Simulating low-temperature properties of three-dimensional frustrated quantum magnets is challenging due to the sign problem and the system sizes required to mitigate substantial finite-size effects. However, there are many experimental examples of three-dimensional crystals that could host exotic low-temperature states of matter, such as quantum spin liquids. We calculate the ground-state phase diagrams of frustrated quantum spin models on the body-centered cubic lattice using neural quantum states. First, we study the antiferromagnetic $J_{1} - J_{2}$ model where we find a direct first-order phase transition between Néel and collinear long-range-ordered phases at $(J_{2} / J_{1})_{c} = 0.705$ , consistent with previous studies. Then, in a tetragonally-distorted variant, proposed as a minimal model of NaCa $_{2}$ Cu $_{2}$ (VO $_{4}$ ) $_{3}$ , we find no evidence of a quantum paramagnetic ground state, with a first-order phase transition between Néel and chain phases at $(J_{2 ab} / J_{1})_{c} = 1.0375$ . Therefore, the ground state of the tetragonally-distorted model does not reproduce the low-temperature magnetic properties of NaCa $_{2}$ Cu $_{2}$ (VO $_{4}$ ) $_{3}$ , and the inclusion of other effects is necessary to rationalize experimental observations.

12 pages, 10 figures

Ground-state phases of S=1/2 Heisenberg models on the body-centered cubic lattice

Abstract

Ground-state phases of $S = 1/2$ Heisenberg models on the body-centered cubic lattice