Quantum Monte-Carlo Pseudo Spin phase transition in metal halide perovskites

Very early commit on an ongoing project. Blog posts about the progress can be read at

Part 1 - http://www.santoshkumarradha.me/blog/2020/julia-MC/

Part 2 - http://www.santoshkumarradha.me/blog/2020/julia-MC2/

Things to do

1. Memory and speed test with system size
2. Fit coupling parameter to real DFT energies
3. MC steps (at T = 0K)

AFM and FM sollution

4. ~Periodic boundary conditions~

5. rotation of tetrahedrons

6. Nearest Neighbor Dipole and Bonding term caculation