Emergence of High-Order Deformation in Rotating Transfermium Nuclei: A Microscopic Understanding

The rotational properties of the transfermium nuclei are investigated in the full deformation space by implementing a shell-model-like approach in the cranking covariant density functional theory on a threedimensional lattice, where the pairing correlations, deformations, and moments of inertia are treated in a microscopic and self-consistent way. The kinematic and dynamic moments of inertia of the rotational bands observed in the transfermium nuclei 252No, 254No, 254Rf, and 256Rf are well reproduced without any adjustable parameters using a well-determined universal density functional. It is found for the first time that the emergence of the octupole deformation should be responsible for the significantly different rotational behavior observed in 252No and 254No. The present results provide a microscopic solution to the longstanding puzzle on the rotational behavior in No isotopes, and highlight the risk of investigating only the hexacontetrapole (/360) deformation effects in rotating transfermium nuclei without considering the octupole deformation.