Stable Universal 1- and 2-Input Single-Molecule Logic Gates.

Liu, Ran; Han, Yingmei; Sun, Feng; Khatri, Gyan; Kwon, Jaesuk; Nickle, Cameron; Wang, Lejia; Wang, Chuan-Kui et al. · Adv Mater · 2022

basic_science · Level V

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Abstract

Controllable single-molecule logic operations will enable development of reliable ultra-minimalistic circuit elements for high-density computing but require stable currents from multiple orthogonal inputs in molecular junctions. Utilizing the two unique adjacent conductive molecular orbitals (MOs) of gated Au/S-(CH<sub>2</sub> )<sub>3</sub> -Fc-(CH<sub>2</sub> )<sub>9</sub> -S/Au (Fc = ferrocene) single-electron transistors (≈2 nm), a stable single-electron logic calculator (SELC) is presented, which allows real-time modulation of output current as a function of orthogonal input bias (V<sub>b</sub> ) and gate (V<sub>g</sub> ) voltages. Reliable and low-voltage (ǀV<sub>b</sub> ǀ ≤ 80 mV, ǀV<sub>g</sub> ǀ ≤ 2 V) operations of the SELC depend upon the unambiguous association of current resonances with energy shifts of the MOs (which show an invariable, small energy separation of ≈100 meV) in response to the changes of voltages, which is confirmed by electron-transport calculations. Stable multi-logic operations based on the SELC modulated current conversions between the two resonances and Coulomb blockade regimes are demonstrated via the implementation of all universal 1-input (YES/NOT/PASS_1/PASS_0) and 2-input (AND/XOR/OR/NAND/NOR/INT/XNOR) logic gates.