Traditional charge-based memories,such as dynamic ran-dom-access memory(DRAM)and flash,are approaching their scaling limits.A variety of resistance-based memories,such as phase-change memory(PCM),magnetic random-access memory(MRAM)and resistive random-access memory(RRAM),have been long considered for emerging memory ap-plications thanks to their non-volatility,fast speed,low power,and compact size for potentially high-density integra-tion.More recently,they are also extensively studied as mem-ristors for neuromorphic computing,which has quite differ-ent requirements on their resistive switching characteristics compared to digital memory application.In the past decade,tremendous progresses,from materials and physical mechan-isms to devices and neuromorphic systems,have been made to advance the field.