Electronic and Magnetic Properties of Layered M 3 Si 2 Te 6 (M = Alkaline Earth and Transition Metals).

Recently, a new layered material, Mn 3 Si 2 Te 6 , was identified to be a semiconductor with nodal-line topological property and ferrimagnetic (FRM) ground state. In this work, we propose a series of structures, M 3 Si 2 Te 6 (M = alkaline earth and transition metals), and systematically investigate their mechanical, magnetic and electronic properties, and the strain effect to enrich the family of the layered materials for practical applications. We find 13 stable structures, including 5 semiconductors (M = Ca, Sr, Fe, Ru and Os) and 8 metals (M = Sc, Ti, Nb, Ta, Cr, Mo, W and Tc). Two structures (M = Ti and Cr) are antiferromagnetic (AFM), while other structures are non-magnetic (NM). Similar to Mn 3 Si 2 Te 6 , the AFM structures exhibit magnetic anisotropy energies (MAE) and semiconductors have anisotropic electron effective masses. We further show that compressions along the z-axis can effectively tune the electronic and magnetic properties, such as the semiconductor-metal and NM-AFM transition in Fe 3 Si 2 Te 6 , the two-fold degeneracy of the valence band maximums (VBMs) in Sr 3 Si 2 Te 6 , as well as the reduced MAE for all magnetic structures. These results demonstrate the diverse properties of the layered M 3 Si 2 Te 6 family and provide promising theoretical predictions for the future design of new layered materials.