Large electro-opto-mechanical coupling in VO2 neuristors

作     者：Khandelwal, Upanya Sandilya, Rama Satya Rai, Rajeev Kumar Sharma, Deepak Mahapatra, Smruti Rekha Mondal, Debasish Bhat, Navakanta Aetkuri, Naga Phani Avasthi, Sushobhan Chandorkar, Saurabh Nukala, Pavan 

作者机构：Center for Nanoscience and Engineering Indian Institute of Science Karnataka Bengaluru560012 India Materials Science and Engineering University of Pennsylvania 3231 Walnut Street Philadelphia19104 United States Solid State and Structural Chemistry Unit Indian Institute of Science Karnataka Bengaluru560012 India 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2023年

核心收录：

主　　题：Vanadium dioxide 

摘      要：Biological neurons are electro-mechanical systems, where the generation and propagation of an action potential is coupled to 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 electromechanical or electrooptical 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 modelling 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, 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. © 2023, CC BY.