Thermodynamic stability across concurrent structural, magnetic, and metal-insulator transition in h-NiS

With the proposed work, we aim to understand the role of the electron, spin, and lattice degrees of freedom (DOF) in h-NiS across the metal-insulator transition (MIT). One promising approach to decipher the contribution from various DOF is to calculate the thermodynamic stability of the metallic and insulating phases. This is done by calculating the phonon, electron, and spin entropy across MIT and determine the dominant contribution to the total entropy. Using inelastic neutron scattering (INS), we plan to measure phonon and magnon scattering intensity, and subsequently correct for background, multiphonon, and multiple scattering to obtain the phonon and magnon density of states (DOS). From measured DOS, we will calculate the phonon and magnon entropy contributions and combine with simulations of the electron entropy to determine the overall thermodynamic stability across the MIT.