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Graphene Quantum Dot Crystal Serving as a Multi‐Qubit Circuit Operating at High Temperatures
Author(s) -
Shafraniuk Serhii E.
Publication year - 2020
Publication title -
advanced quantum technologies
Language(s) - English
Resource type - Journals
ISSN - 2511-9044
DOI - 10.1002/qute.202000062
Subject(s) - zigzag , qubit , graphene , coherence (philosophical gambling strategy) , graphene quantum dot , electron , quantum dot , wave function , crystal (programming language) , wigner crystal , physics , condensed matter physics , atomic physics , nanodot , electron density , quantum , quantum mechanics , optoelectronics , geometry , mathematics , computer science , programming language
Localized states (LS) of electrons are studied in clusters and in periodic arrays of graphene quantum dots (GQD) formed using narrow graphene stripes with either armchair or zigzag shape of atomic edges. Basic electronic parameters of the system such as the LS energies E n , inter‐level splitting Δ n , wavefunction coherence, and the inter‐dot coupling are controlled by applying the electric potentials φ lg to the electrodes. The electron density of states N ( ε ) of the periodic quantum dot array regarded as 1D crystal (GC) represents a sequence of very sharp peaks corresponding to LS levels. The spatial coherence parameterΞ GC = 1 / ( d · ℑ κ )( d is the GC period and κ is the electron wave vector) is estimated asΞ GC ≃ 5 to 20 , suggesting that the electron coherence involves large clusters of GQD by spreading over 5–20 periods in the artificial crystal. Furthermore, the coherence time τ c , which is determined by inelastic electron–phonon collisions is remarkably long,τ c ≈ 2 to 100 ns even at temperatures T ≈ 300 K. The above properties of GC open new opportunities for building of the all‐electrically controllable multi‐qubit circuits operating at high temperatures.