Quantum Hamiltonian Computing (QHC) Logic Gates

Abstract

The quantum graph of a two-input–one-output QHC Boolean logic gate was used to design a very simple dangling bond QHC logic gate. On an Si(100):H surface and in the vertical single atom manipulation mode, an LT-UHV-STM was used for atom-by-atom construction of this QHC logic gate using only three dangling bonds. As expected, the experimental measurement shows a NOR gate at a 1.3-V positive bias voltage and an OR gate at −1.8 V. The same Boolean logical functions were also obtained in our quantum tunneling calculations, where the geometry and the electronic properties of the Si surface were determined using DFT. The surface Green function matching (SGFM) method was used to calculate the dI/dV spectra in a vertical STM measurement configuration and the tunneling current intensity through the DB gate in a planar two metallic nanopads configuration, confirming the NOR and the OR function of the QHC gate.