with spin-induced electric polarization*

Layered polar magnetic semiconductors are currently of emerging interest for their nonlinear and various functional properties. To date, only few layered ferroelectrics have been found while plenty of layered materials show long-range magnetic ordering. In this talk, we report a new layered quaternary chalcogenide MnCuSiTe₃ which shows a polar structure at room temperature and multiple magnetic transitions at low temperature. We demonstrated its polar nature with piezoelectric response along with a large Second Harmonic Generation signal at room temperature. Moreover, we also found a remarkable electric polarization below the long-range antiferromagnetic transition at T_N=35K. Further, we also probed pyroelectric current below T_N. These results suggest MnCuSiTe₃ may exhibit a multiferroic state below T_N.