Mechanical Control of Electroresistive Switching

Abstract

Hysteretic metal-insulator transitions (MIT) mediated by ionic dynamics or ferroic phase transitions underpin emergent applications for nonvolatile memories and logic devices. The vast majority of applications and studies have explored the MIT coupled to the electric field or temperarture. Here, we argue that MIT coupled to ionic dynamics should be controlled by mechanical stimuli, the behavior we refer to as the piezochemical effect. We verify this effect experimentally and demonstrate that it allows both studying materials physics and enabling novel data storage technologies with mechanical writing and current-based readout.

Mechanical Tuning of LaAlO3/SrTiO3 Interface Conductivity

“…This mechanism, termed piezochemical oxidation, is known to increase the resistivity of NiO by restoring its full oxygen stoichiometry. 31 In our case, the sign of the resistance switching is opposite, because the consequence of pushing oxygen vacancies away from the tip is to drive them towards the LaAlO 3 /SrTiO 3 interface, which results in higher electron density and thus higher conductivity/lower resistivity. …”

Local Probing of Ferroelectric and Ferroelastic Switching through Stress‐Mediated Piezoelectric Spectroscopy

“…[27] However, the films probed in our work are substantially thicker: the field gradients exerted by the tip within the sample are expected to permeate a much smaller fraction of the hundreds of nanometers thick films, and hence the switching we observed cannot be uniquely explained by the flexoelectric mechanism. Other potential mechanisms, such as piezochemical effect, [38] have also been used to explain mechanical writing in thin films of oxides but the films used in such studies were also quite thin (50 nm). In fact, chemical coupling with electromechanical response usually requires film thicknesses comparable to the diffusion length scale for the mobile chemical species, [38] which is indeed substantially smaller than the 660 nm thick PZT films under discussion.…”

“…Other potential mechanisms, such as piezochemical effect, [38] have also been used to explain mechanical writing in thin films of oxides but the films used in such studies were also quite thin (50 nm). In fact, chemical coupling with electromechanical response usually requires film thicknesses comparable to the diffusion length scale for the mobile chemical species, [38] which is indeed substantially smaller than the 660 nm thick PZT films under discussion. The most likely mechanism for mechanical writing in these films is ferroelastic domain wall movement caused by external mechanical forces applied via the tip.…”

Oxide Electronics and Vanadium Dioxide Perspective: A Review

“…15. Various versions of memory devices utilizing the effect of MIT in vanadium oxides has also been discussed in the literature [30], [31], [156], [162], [163], [171], [172]. It is pertinent to quote here also the work [173] where the experiments on memory switching in thin-film V 2 O 5 -based structures have first been described.…”

“…that similar factually to an HD or CD, based on the MIT in VO 2 has been designed [144], [162], and a flexible display is feasible on the basis of the electrolyte-less electrochromic effect in V 2 O 5 -gel films [175]. Note however that the main requirement to the MIT-based oxide electronics is still its ability to be scaled down to nano-dimensions.…”