Quantum Interference Transistors (Quits) and Coupled Quantum Dot (QD) Structures with Tunneling Barriers for Multi-State Logic, In-Memory and Quantum Computing
F. Jain, Raja Hari Gudlavalleti, John A. Chandy, Evan K. Heller · International Journal of High Speed Electronics and Systems · 2025
This paper describes a quantum dot (QD) quantum interference transistor (QUIT) having two identical electron transport channels with variable gate or stub voltages to control [Formula: see text]–[Formula: see text] characteristics. The two channels share common [Formula: see text]–[Formula: see text] source ([Formula: see text] and drain ([Formula: see text] contacts. The [Formula: see text] region of [Formula: see text] in both arms is separated by a thin barrier layer (e.g. SiO2, HfO[Formula: see text] from the [Formula: see text] SiO[Formula: see text] cladded Si coupled quantum dots. Here, eight-to-twelve QDs form a finite quantum dot superlattice (QDSL) exhibiting sharp mini-energy bands. The switching in QD-QUIT is controlled by: (i) difference in tunneling barrier gate voltages VGTB in both arms at a given VDS, (ii) gate voltages on QD clusters in each arm, (iii) axial current or magnetic field along [Formula: see text]-axis perpendicular to the [Formula: see text]–[Formula: see text] plane via Aharonov–Bohm effect. The finite QDSL electron transport channel is proposed for spin-based qubits operating at cryogenic temperatures. Furthermore, the finite QDSL, constructed using doped 29Si isotope is known to improve coherence time while using more than two electrons. In particular, we present eight-coupled QDs forming a finite quantum dot superlattice (F-QDSL) exhibiting sharp mini-energy levels with very high microwave/millimeter wave/IR operations. Novel multi-state QDC [Formula: see text]-FETs realized on [Formula: see text]-epi along with [Formula: see text]-QDC-FETs are reported in a CMOS-like logic. In addition, application of quantum dot channels (QDC) [Formula: see text]-FETs and [Formula: see text]-FETs is discussed to change states of QD-NVRAMs for in-memory computing. Finally, cryogenic QD-QUITs, [Formula: see text]- and [Formula: see text]-FETs, multi-electron Si coupled quantum dots are investigated to form exchange only (EO) grids for quantum computing.