Theoretical interpretation for the occurrence of a Lifshitz point in MnP

We present a theoretical interpretation for the occurrence of a Lifshitz point in the field-temperature phase diagram of MnP. Our mean-field calculations, which are based on a localized spin Hamiltonian, are in qualitative agreement with recently reported experiments. In particular, we obtain asymptotic expressions for the phase boundaries, which meet tangentially at the Lifshitz point, and for some other thermodynamic quantities of interest, such as the longitudinal and transverse susceptibilities. A renormalization-group argument also supports the conclusion that the Lifshitz point in MnP is of a uniaxial one-component type.