Wei Teng, Shengnan Wang, Yu Zhang
A simple algebraic scheme incorporating the prolate-oblate shape phase transition (SPT) is proposed within the framework of the interacting boson model to describe the quadrupole deformation features of Xe isotopes near $A=130$. The analysis demonstrates that novel $\ensuremath{\gamma}$-soft modes, characterized by the unusual quadrupole moments $Q({2}_{1}^{+})<0$ and $0<Q({2}_{2}^{+})\ensuremath{\ll}|Q({2}_{1}^{+})|$, can emerge near the critical point of this SPT. This finding is further applied to interpret the properties of low-lying states in the relevant Xe nuclei, particularly the experimentally observed nearly vanishing spectroscopic quadrupole moment $Q({2}_{2}^{+})$, thereby offering new insights into the structure of a $\ensuremath{\gamma}$-soft deformed nucleus.