Hydrostatic pressure influence on magnetic phase diagram and structural parameters of SrTcO3 from first-principles calculations

The effects of hydrostatic pressure of SrTcO3 are investigated by means of generalized gradient approximation (GGA) plus on-site Coulomb interaction corrections (GGA+U) method within the framework of density functional theory (DFT). Magnetic phase diagrams and structural parameters of SrTcO3 as a function of pressure are predicted. The magnetic ground state of SrTcO3 is found to keep in a G-type antiferromagnetic (G-AFM) structure under the pressure varying from 0 to 100 GPa. With the increase of the pressure, magnetic exchange energy increases, indicating a higher magnetic ordering temperature for SrTcO3 under a larger pressure. Besides the volume of the unit cell, lattice constants, and the bond length, the angles between typical Tc-O-Tc and Sr-O-Sr also decrease with the pressure, leading to strong structural distortions. Very obvious displacements of Sr and O atoms are observed under the pressure. Our work provides necessary understanding on electronic structures of SrTcO3 under high pressures.