Room-temperature memristive switching between charge density wave states

Abstract

Control over charge density wave (CDW) states is technologically promising for the development of ultra-efficient memory devices. However, using electrical pulses for non-volatile resistance switching involving CDW states has so far been limited to cryogenic temperatures. In this work, we investigate a recently discovered layered semiconductor EuTe4, which exhibits the coexistence of distinct CDW orders. We report that electrical pulses can be used for excitation to non-equilibrium, yet stable electronic states across a broad temperature range from 6 K to 400 K. We find that switching occurs through a non-thermal pathway and is reversible via a thermal erase procedure. The resistance of the new electronic state is tunable by the pulse voltage, so the device acts as a memristor. Calculations show fixed bilayer CDW, whereas CDW in single layers shows bistability due to weak Eu-Te links. Low-voltage, fast, and energy-efficient CDW switching holds potential for memristor applications.