The hot nucleus ${}^{171}\mathrm{Yb}$ is investigated by the covariant density functional theory with the PC-PK1 effective interaction. The thermodynamic quantities are evaluated with the canonical ensemble theory. The pairing correlations is treated by the shell-model-like approach, in which the particle numbers are conserved strictly and in which the blocking effect is handled exactly. An S-shaped heat capacity versus temperature of ${}^{171}\mathrm{Yb}$ appears. It has been studied in terms of the blocking effect, the single-particle levels, the pairing gap, and defined seniority components, and compared to the heat capacity of ${}^{172}\mathrm{Yb}$. The pairing transition from the superfluid state to the normal state can result in the S-shaped heat capacity of ${}^{172}\mathrm{Yb}$ where the one-pair-broken and two-pair-broken states dominate, while the single-particle level structure near the Fermi surface is associated with the S-shaped heat capacity of ${}^{171}\mathrm{Yb}$. For odd-$A$ nuclei, although the one-pair-broken and two-pair-broken states still contribute, the pairing gap and the pairing transition is relatively weak. The S-shaped heat capacity could be affected due to the blocking of the single-particle level near the Fermi surface.

• Received 7 April 2021
• Accepted 21 July 2021

DOI:https://doi.org/10.1103/PhysRevC.104.024303