Atomic‐Scale Characterization of Negative Differential Resistance in Ferroelectric Bi 2 WO 6

Negative differential resistance (NDR), a quantum nonlinear electron transport process, has long attracted research interest owing to its intriguing underlying physics and promising applications in high‐speed electronics. Here, the authors report the NDR behavior in (001)‐oriented ferroelectric Bi 2 WO 6 using scanning tunneling microscopy (STM). The current–voltage characteristics of the diode configuration consisting of an STM tip over the [BiO] + ‐[WO 4 ] 2− ‐[BiO] + terrace exhibit NDR features. Scanning tunneling spectroscopy combined with density functional theory calculations indicates that the observed NDR results from robust resonant tunneling through confined energy levels within the 2D [WO 4 ] 2− layer. The atomically resolved NDR found in such a transition metal oxide offers a unique band structure for novel ferroelectric‐based devices.