Singlet Semiconductor to Ferromagnetic Metal Transition in FeSi

Adding the local Coulomb repulsion to the local density approximation, the so-called $\mathrm{LDA}+U$ scheme, leads us to predict a first order transition from a singlet semiconductor to ferromagnetic metal in FeSi with increasing magnetic field. Extensions to finite temperature lead to the interpretation that the anomalous behavior at room temperature and zero field arises from proximity to the critical point of this transition. This critical point at a finite field may be accessible in currently available magnetic fields.