Structural, magnetic and ferroelectric properties of VOBr<sub>2 </sub>monolayer: A first-principles study

On the basis of first-principles calculations, structure, magnetism and ferroelectricity VOBr<sub>2</sub> monolayer are studied systematically in present work. The calculation results indicate that a spontaneous ferroelectric distortion takes place at low temperature, causing structure to transform from centrosymmetric paraelectric phase one. In contrast with its sister compound VOI<sub>2</sub>, dimerization V is unstable may quench local magnetic moment on ions. Additionally, easy magnetization axis in-plane along <i>a</i>-axis, coupling between adjacent moments antiferromagnetic both <i>a</i>-axis <i>b</i>-axis. Moreover, displacement ions occurs V—O—V chains direction, resulting polarization about 40 μC/cm<sup>2</sup>. Comparing ferro-to-paraelectric reversal pathway, energy barrier can be effectively reduced for switching partial or individual chains. It reasonable believe dipole flipping specific chain achieved through moderate external field, thereby providing new direction designing low-energy-consumption high-density memory device.