Structural Engineering Enables Suppressed Ion Migration and Enhanced Hard X‐Ray Detection Performance in Novel Oxide Single Crystals

X‐ray detectors have obtained great attention in medical diagnostics, security checks, and space exploration. However, ion migration of X‐ray detectors results in dark current drift, low signal‐to‐noise ratio, and degradation of detection performance. Here, ion migration properties of Li 2 ZrTeO 6 and ZrTe 3 O 8 are comprehensively investigated by theoretical analysis and experimental results. ZrTe 3 O 8 single crystal exhibits a high migration barrier of O 2− ion (1.89 eV), a high ion activation energy (992.6 meV), and an ultralow dark current drift (3.16 × 10 −9 nA cm −1 s −1 V −1 ) due to the absence of Li + cations and the disconnecting of adjacent ZrO 6 octahedra, which is better than Li 2 ZrTeO 6 single crystal. These results show that the absence of low atomic number elements and the disconnecting of adjacent octahedra in crystal structure can inhibit ion migration essentially. Owing to a high resistivity, a high mobility lifetime product, suppressed ion migration, and the lone‐pair electrons enhancement effect of detection performance for Te 4+ cations, ZrTe 3 O 8 X‐ray detector shows a high sensitivity of 348 µC Gy −1 cm −2 and an ultralow detection limit of 15.4 nGy air s −1 . This work proposes an effective strategy to inhibit ion migration and proves the enhancement effect of detection performance for the cations containing lone‐pair electrons.