Harnessing the Metal–Insulator Transition of VO₂ in Neuromorphic Computing

Abstract

Future‐generation neuromorphic computing seeks to overcome the limitations of von Neumann architectures by colocating logic and memory functions, thereby emulating the function of neurons and synapses in the human brain. Despite remarkable demonstrations of high‐fidelity neuronal emulation, the predictive design of neuromorphic circuits starting from knowledge of material transformations remains challenging. VO2 is an attractive candidate since it manifests a near‐room‐temperature, discontinuous, and hysteretic metal–insulator transition. The transition provides a nonlinear dynamical response to input signals, as needed to construct neuronal circuit elements. Strategies for tuning the transformation characteristics of VO2 based on modification of material properties, interfacial structure, and field couplings, are discussed. Dynamical modulation of transformation characteristics through in situ processing is discussed as a means of imbuing synaptic function. Mechanistic understanding of site‐selective modification; external, epitaxial, and chemical strain; defect dynamics; and interfacial field coupling in modifying local atomistic structure, the implications therein for electronic structure, and ultimately, the tuning of transformation characteristics, is emphasized. Opportunities are highlighted for inverse design and for using design principles related to thermodynamics and kinetics of electronic transitions learned from VO2 to inform the design of new Mott materials, as well as to go beyond energy‐efficient computation to manifest intelligence.

Unconventional Giant “Magnetoresistance” in Bosonic Semiconducting Diamond Nanorings

“…The DNRs show an R ( T ) distinctly different from that of the starting material (Figure 2d). Below the T c of the DTFs, the R ( T ) of the DNRs first overshoots the residual resistance by 260–430%, which turns into a decrease at lower temperatures and then regains its increasing trend below about 1 K. These unconventional R ( T ) behaviors distinguish themselves from previously reported data in the following three aspects: 1) despite its similarity to the metal–insulator transition in materials such as VO 2 , [ 33 ] the sharp R ( T ) increase implies its correlation with the resistive superconducting transition in the starting material by onsetting at about T c , and thus cannot be viewed as a fermionic transition; 2) in contrast to the low‐temperature bosonic insulating states in highly disordered superconductors with a weakly insulating normal state, [ 34 ] the sharp R ( T ) increase in the DNRs evolves from an established metallic normal state; 3) when approaching zero temperature, R ( T ) remains well above the residual resistance value and regains its increasing trend at low temperatures, rather than evolving into a superconducting transition as in the previously reported narrow resistance peaks. [ 13–26 ]…”

Effect of Stereochemically Active Electron Lone Pairs on Magnetic Ordering in Trivanadates

“…Given the complexity of V−O Ellingham and Pourbaix diagrams, control of pH and redox potential is imperative to arrive at the desired oxygen stoichiometries and is achieved here with the addition of H 2 O 2 . 25,26 Synthesis of RbV 3 O 8 Single Crystals. Single crystals of RbV 3 O 8 were grown according to a modified hydrothermal method.…”

Modulation of Switching Characteristics in a Single VO2 Nanobeam with Interfacial Strain via the Interconnection of Multiple Nanoscale Channels

“…One of the recent important issues concerning VO 2 is the control of its physical properties to provide useful functionalities like nonlinear conductance, hysteresis behavior, and abrupt transition for potential applications in smart windows, switch devices, and neuromorphic computing. ,,,,− The physical properties of the VO 2 -based system interfacing with a substrate are strongly affected by the metal (M) and insulator (I) domain configuration. For example, polycrystalline VO 2 planar thin films show randomly mixed coexistence of M-I domains, whereas one-dimensional (1D) and two-dimensional (2D) VO 2 single crystals exhibit periodic organization of alternating M-I domains during the phase transformations. , Therefore, the manipulation of the M-I domain configuration in VO 2 can play a critical role in controlling the phase transition properties for electronic and optoelectronic device applications.…”