Tetrahedral and triangular deformations of Z=N nuclei in mass region A∼60–80

We study static non-axial octupole deformations in proton-rich Z=N nuclei, 64Ge, 68Se, 72Kr, 76Sr, 80Zr and 84Mo, by using the Skyrme Hartree-Fock plus BCS calculation with no restrictions on the nuclear shape. The calculation predicts that the oblate ground state in 68Se is extremely soft for the Y33 triangular deformation, and that in 80Zr the low-lying local minimum state coexisting with the prolate ground state has the Y32 tetrahedral deformation.