Khandelwal, U and Sandilya, RS and Rai, RK and Sharma, D and Mahapatra, SR and Mondal, D and Bhat, N and Aetkuri, NP and Avasthi, S and Chandorkar, S and Nukala, P (2024) Large electro-opto-mechanical coupling in VO2 neuristors. In: Applied Physics Reviews, 11 (2).
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Abstract
Biological neurons are electro-mechanical systems, where the generation and propagation of an action potential are coupled to the generation and transmission of an acoustic wave. Neuristors, such as VO2, characterized by insulator-metal transition (IMT) and negative differential resistance, can be engineered as self-oscillators, which are good approximations of biological neurons in the domain of electrical signals. In this study, we show that these self-oscillators are coupled electro-opto-mechanical systems, with better energy conversion coefficients than the conventional electro-mechanical or electro-optical materials. This is due to the significant contrast in the material's resistance, optical refractive index, and density across the induced temperature range in a Joule heating driven IMT. We carried out laser interferometry to measure the opto-mechanical response while simultaneously driving the devices electrically into self-oscillations of different kinds. We analyzed films of various thicknesses, engineered device geometry, and performed analytical modeling to decouple the effects of refractive index change vis-à -vis mechanical strain in the interferometry signal. We show that the effective piezoelectric coefficient (d13*) for our neuristor devices is 660 ± 20 pm/V, with a 31 internal energy conversion efficiency, making them viable alternatives to Pb-based piezoelectrics for MEMS applications. Furthermore, we show that the effective electro-optic coefficient (r13*) is �22 nm/V, which is much larger than that in thin-film and bulk Pockels materials. © 2024 Author(s).
| Item Type: | Journal Article |
|---|---|
| Publication: | Applied Physics Reviews |
| Publisher: | American Institute of Physics |
| Additional Information: | The copyright for this article belongs to authors. |
| Keywords: | Acoustic wave propagation; Energy conversion efficiency; Laser interferometry; Metal insulator transition; Piezoelectricity; Refractive index, Acoustics waves; Action-potentials; Biological neuron; Electrical signal; Electromechanical systems; Insulator metal transition; Mechanical coupling; Negative differential resistances; Optomechanical; Self-oscillators, Vanadium dioxide |
| Department/Centre: | Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering |
| Date Deposited: | 28 May 2024 06:41 |
| Last Modified: | 28 May 2024 06:41 |
| URI: | https://eprints.iisc.ac.in/id/eprint/85019 |
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