This code builds upon the FastKPM library to enable fast, linear-scaling simulations of the classical Kondo lattice model (KLM).

The model contains itinerant electrons, whose spins couple to classical magnetic moments localized on each site. After "integrating out" the itinerant electrons, the effective interactions between magnetic moments can be long-range and many-body. For example, at weak coupling J, the effective interactions are of the RKKY type. This code allows arbitrary J, and treats long-range interactions correctly.

With GPU acceleration enabled, this code readily enables simulating the dynamics of 10k interacting magnetic moments, or even more.

Building is handled with CMake.

The FastKPM library should already be compiled and installed. Kondo will then automatically link to it.

This package includes tests. Please start with bin/test_kpm and bin/test_kondo to make sure everything is installed correctly.

Still needs to be documented...

An early version of this method was presented in:

• Efficient Langevin simulation of coupled classical fields and fermions, Barros et al., PRB (2013).

However, the method has evolved significantly since then! Two important improvements are gradient-based probing and more accurate integration of the magnetic dynamics.

This code has been used in the following research papers:

• Exotic magnetic orderings in the kagome Kondo-lattice model, Barros et al., PRB (2014)
• Vortex Crystals with Chiral Stripes in Itinerant Magnets, Ozawa et al., JPSJ (2016)
• Resistivity Minimum in Highly Frustrated Itinerant Magnets, Wang et al., PRL (2016)
• Zero-Field Skyrmions with a High Topological Number in Itinerant Magnets, Ozawa et al., PRL (2017)
• Shape of magnetic domain walls formed by coupling to mobile charges, Ozawa et al., PRB (2017)
• Simulated floating zone method, Ozawa et al., JPCS (2017)
• Semiclassical dynamics of spin density waves, Chern et al., PRB (2018)
• Multiple-Q magnetic orders in Rashba-Dresselhaus metals, Okada et al., PRB (2018)
• Nonequilibrium dynamics of superconductivity in the attractive Hubbard model, Chern et al., PRB (2019)

Please let us know if you use this code in your work!

If you find this code useful, please cite our gradient-based probing paper:

@article{doi:10.1063/1.5017741,
author = {Wang, Zhentao and Chern, Gia-Wei and Batista, Cristian D. and Barros, Kipton},
title = {Gradient-based stochastic estimation of the density matrix},
journal = {J. Chem. Phys.},
volume = {148},
pages = {094107},
year = {2018},
}

The primary authors are Kipton Barros (LANL) and Zhentao Wang (ZJU).