The atomic-scale behaviors of an amorphous (a-) $\text{ZrO}_{2}/\text{TaON}$ interface are investigated by ab initio calculations. The results indicate a high ion migration barrier at the interface, which contributes to the over-all ferroelectric-like hysteresis of $\mathrm{a}-\text{ZrO}_{2}$ thin films. This work facilitates further investigations on the mechanisms and performance of ferroelectric-like insulator films which have great potential in the applications of the emerging non-volatile memories, negative capacitance field-effect transistors, neuro-morphic devices, etc.