The polar metallic phase is an unusual metallic phase of matter containing long-range ferroelectric (FE) order in the electronic and atomic structure. Distinct from the typical FE insulating phase, this phase spontaneously breaks the inversion symmetry without global polarization. Unexpectedly, the FE order is found to be dramatically suppressed and destroyed at moderate ~ 10% carrier density. Here, we propose a general mechanism based on carrier-induced quantum fluctuations to explain this puzzling phenomenon. The quantum kinetic effect would drive the formation of polaronic quasi-particles made of the carriers and their surrounding dipoles. The disruption in dipolar directions can therefore weaken or even destroy the FE order. We demonstrate such polaron formation and the associated FE suppression via a concise model using exact diagonalization, perturbation, and quantum Monte Carlo approaches. This quantum mechanism also provides an intuitive picture for many puzzling experimental findings, thereby facilitating new designs of multifunctional FE electronic devices augmented with quantum effects.

极性金属相是一种不寻常的物质金属相，在电子和原子结构中含有长程铁电（FE）有序。与典型的有限元绝缘相不同，该相自发地打破了反演对称性，而没有全局极化。出乎意料的是，发现 FE 序在中等~10% 的载流子密度下被显着抑制和破坏。在这里，我们提出了一种基于载流子引起的量子涨落的通用机制来解释这种令人费解的现象。量子动力学效应将驱动由载流子及其周围偶极子组成的极化准粒子的形成。因此，偶极方向的破坏会削弱甚至破坏有限元秩序。我们通过使用精确对角化的简明模型展示了这种极化子的形成和相关的有限元抑制，扰动和量子蒙特卡罗方法。这种量子机制还为许多令人费解的实验结果提供了直观的图景，从而促进了增强量子效应的多功能有限元电子设备的新设计。