Intrinsic polar metals are rare, especially in oxides, because free electrons screen electric fields in a metal and eliminate the internal dipoles that are needed to break inversion symmetry. Here we use first-principles high-throughput structure screening to predict a new polar metal in bulk and thin film forms. After screening more than 1000 different crystal structures, we find that ordered BiPbTi₂O₆ can crystallize in three polar and metallic structures, which can be transformed between via pressure or strain. In a heterostructure of layered BiPbTi₂O₆ and PbTiO₃, multiple states with different relative orientations of BiPbTi₂O₆ polar displacements, and PbTiO₃ polarization, can be stabilized. At room temperature, the interfacial coupling enables electric fields to first switch PbTiO₃ polarization and subsequently drive 180° change of BiPbTi₂O₆ polar displacements. At low temperatures, the heterostructure provides a tunable tunnelling barrier and might be used in multi-state memory devices.

本征极性金属非常罕见，尤其是在氧化物中，因为自由电子屏蔽了金属中的电场并消除了破坏反演对称性所需的内部偶极子。在这里，我们使用第一性原理高通量结构筛选来预测散装和薄膜形式的新型极性金属。在筛选了1000多种不同的晶体结构后，我们发现有序的BiPbTi ₂ O ₆可以在三种极性和金属结构中结晶，可以通过压力或应变之间进行转换。在分层BiPbTi的异质结构₂ ö ₆和的PbTiO ₃，多个状态与BiPbTi的不同的相对取向₂ ö ₆极性位移和PbTiO ₃极化可以稳定。在室温下，界面耦合使电场能够首先切换PbTiO ₃极化并随后驱动BiPbTi ₂ O ₆极性位移发生180°变化。在低温下，异质结构提供了可调的隧道势垒，可用于多状态存储设备。