Ferroelectricity Driven by the Noncentrosymmetric Magnetic Ordering in Multiferroic TbMn_2O_5: A First-Principles Study

摘要

The ground state structural, electronic, and magnetic properties of multiferroic TbMn_2O_5 are investigated via first-principles calculations. We show that the ferroelectricity in TbMn_2O_5 is driven by the noncentrosymmetric magnetic ordering, without invoking the spin-orbit coupling and noncollinear spins. The intrinsic electric polarization in this compound is calculated to be 1187 nC cm~(-2), an order of magnitude larger than previously thought.