Peculiarities of electron transport and resistive switching in point contacts on TiSe2, TiSeS and CuxTiSe2

TL;DR

This study reports resistive switching in point contacts on TiSe2 and its derivatives, driven by electric field-induced stoichiometry changes, with potential applications in non-volatile memory devices.

Contribution

It is the first to observe resistive switching in TiSe2-based point contacts and links this effect to vacancy drift and heating, expanding the understanding of their electronic properties.

Findings

Resistive switching occurs between metallic and semiconducting states.

Resistance difference can reach up to two orders of magnitude at room temperature.

Switching is driven by electric field-induced vacancy drift and heating effects.

Abstract

TiSe2 has received much attention among the transition metals chalcogenides because of its thrilling physical properties concerning atypical resistivity behavior, emerging of charge density wave (CDW) state, induced superconductivity etc. Here, we report discovery of new feature of TiSe2, namely, observation of resistive switching in voltage biased point contacts (PCs) based on TiSe2 and its derivatives doped by S and Cu (TiSeS, CuxTiSe2). The switching is taking place between a low resistive mainly metallic-type state and a high resistive semiconducting-type state by applying bias voltage (usually below 0.5V), while reverse switching takes place by applying voltage of opposite polarity (usually below 0.5V). The difference in resistance between these two states can reach up to two orders of magnitude at the room temperature. The origin of the effect can be attributed to the variation of stoichiometry in PC core due to drift/displacement of Se/Ti vacancies under high electric field. Additionally, we demonstrated, that heating takes place in PC core, which can facilitate the electric field induced effect. At the same time, we did not found any evidence for CDW spectral features in our PC spectra for TiSe2. The observed resistive switching allows to propose TiSe2 and their derivatives as the promising materials, e.g., for non-volatile resistive random access memory (ReRAM) engineering.