Percolation model of VO2.

Requires the following packages to build on Mint Debian: gsl-bin libgsl0ldbl libgsl0-dev

To build on Fedora, requires: gsl gsl-devel

Description of the model

Ground state: atoms are all dimerized, which prevents long-range hopping. Atoms can be thermally excited to the metallic state.

Costs energy Delta to move an atom from dimer to metal. If both atoms in a dimer are moved to the metal, gain back energy V.

Electrons hop within a percolation network of metallic atoms. Hopping onto dimer sites is renormalized away, leading to nnn hopping within the metal.

First step: Ising-like Monte Carlo in atom excitation variables {nu(i)=0, 1}. Study the formation of the percolation network without including electrons.

Diagonalizing the electron hopping Hamiltonian isn't trivial.
Need a strategy to estimate whether a configuration of nu(i)'s is worth allowing before diagonalization.

Notes

Monte Carlo implementation inspired by this one in Fortran.

gofmt pre-commit hook is helpful for commits.