Work

Path-integral spin dynamics with exchange and external field

Year: 2025

Type: article

Abstract: In this work, we propose a path-integral-inspired formalism for computing the quantum thermal expectation values of spin systems subject to magnetic fields that can be time dependent and can accommodate the presence of Heisenberg exchange interactions between the spins. This is done by deriving an effective magnetic field from the quantum partition function of the system to use in classical atomistic spin dynamics simulations and generalizes the formalism presented in our previous work []. In special cases where the effective field can be computed exactly, we compare our results with exact/numerical diagonalization methods for both ferromagnetic and antiferromagnetic coupling. We show that our method works well across a large temperature range and can reproduce quantum expectation values for antiferromagnetic coupling, which is usually not possible with classical models.

Source: Physical review. B./Physical review. B

DOI: 10.1103/m6vx-cl3v

Authors: Thomas Nussle, Stam Nicolis, Iason Sofos, Joseph Barker

Institutions: University of Leeds, Institut Denis Poisson

Language: English

Topic: Advanced Condensed Matter Physics

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funders: Royal Society, Engineering and Physical Sciences Research Council

Awards: Path Integral Quantum Spin Dynamics, International Network for Spintronics: From Material Development to Novel Energy Efficient Technologies