[21p-B31-1~14] 21.1 Joint Session K "Wide bandgap oxide semiconductor materials and devices"

[21p-B31-12] First-principles calculation of elastic and piezoelectric constants and spontaneous polarization of Pna2₁-(In_xM_1-x)O₃(M=Al, Ga)

〇Jun Hasegawa¹, Kazuhiro Shimada¹ (1.Kanto Gakuin Univ.)

Keywords:sesqui-oxides, first-principles calculation

The orthorhombic sesqui-oxides with the space group Pna2₁, which is one of the metastable structures of the group III sesqui-oxides, are predicted to have large piezoelectric constants and spontaneous polarization than nitride semiconductors. The interface charge made by piezoelectric and spontaneous polarization between different materials plays an important role in high electron mobility transistors, so that the information on polarization is very important for the design of such electronic devices. In this study, we perform first principle calculations to investigate the mole fraction dependence of lattice parameters, elastic and piezoelectric constants, and spontaneous polarization based on density functional theory, considering the device design using the alloys of orthorhombic In₂O₃, Al₂O₃ and Ga₂O₃. The calculations are performed using 2x1x1 unit cells including 80 atoms to simulate random atomic configuration using special quasi-random structure approach. The computational results indicate non-linear behavior for the mole fraction dependence of the lattice parameters, elastic and piezoelectric constants, spontaneous polarization.