Multistate Ferroelectric Memory for in‐Memory Differential Computing in C ‑Axis‑Oriented HZO‑ZrO 2 Films Enabled by Interfacial Engineering

ABSTRACT The von Neumann bottleneck limits energy‐efficient computing. While ferroelectric hafnium zirconium oxide (HZO) memories are promising for in‐memory computing, achieving high speed, endurance, and reliable multilevel control remains challenging. This work addresses these challenges through interfacial engineering with an ultrathin ZrO 2 seed layer. Atomic‐resolution microscopy reveals that this interlayer promotes preferential c ‐axis orientation of the ferroelectric orthorhombic phase, aligning the polarization axis with the applied electric field. This enables nanosecond (6 ns) switching, long‐term retention (>10 4 s), and stable programming of 10 distinct polarization states. Based on these capabilities, we demonstrate an in‐memory differentiator within a single device. Analog values encoded as discrete polarization levels enable direct first‐ and second‐order derivative calculations, where the transient switching current represents the differential output. This atomic‐scale structural control provides a materials‐to‐system link that may facilitate real‐time, energy‐efficient data processing.