Magnetism and the origin of ferroelectricity in the multiferroic ${\text{MnWO}}_4$ are studied using ab initio electronic-structure calculations, correctly reproducing the magnetic ground state. The calculated ferroelectric polarization is in good agreement with experiments. Our results reveal that spin-orbit interaction is necessary and sufficient to explain the observed ferroelectric polarization, establishing an entirely electronic origin of ferroelectricity in ${\text{MnWO}}_4$. The origin of spin-orbit interaction in this compound with a nominally $d^{5}L=0$ orbitally quenched state is elucidated by analyzing results of x-ray absorption spectroscopy.

• Received 30 April 2010

DOI:https://doi.org/10.1103/PhysRevB.81.212406