Quasi‐Solid‐State Single‐Atom Transistors

Abstract

The single-atom transistor represents a quantum electronic device at room temperature, allowing the switching of an electric current by the controlled and reversible relocation of one single atom within a metallic quantum point contact. So far, the device operates by applying a small voltage to a control electrode or "gate" within the aqueous electrolyte. Here, the operation of the atomic device in the quasi-solid state is demonstrated. Gelation of pyrogenic silica transforms the electrolyte into the quasi-solid state, exhibiting the cohesive properties of a solid and the diffusive properties of a liquid, preventing the leakage problem and avoiding the handling of a liquid system. The electrolyte is characterized by cyclic voltammetry, conductivity measurements, and rotation viscometry. Thus, a first demonstration of the single-atom transistor operating in the quasi-solid-state is given. The silver single-atom and atomic-scale transistors in the quasi-solid-state allow bistable switching between zero and quantized conductance levels, which are integer multiples of the conductance quantum G = 2e /h. Source-drain currents ranging from 1 to 8 µA are applied in these experiments. Any obvious influence of the gelation of the aqueous electrolyte on the electron transport within the quantum point contact is not observed.

Recent Advances of Quantum Conductance in Memristors

“…Historically, quantum conductance was first discovered in the 2D electron gas system of a GaAs‐AlGaAs heterostructure at 0.6 K by van Wees et al in 1988, and then in various metal nanowires or quantum point contacts constructed by scanning tunneling microscope, mechanically controllable break junction technique, electrochemical deposition, and etc. While quantum conductance in memristors was already reported in the early 1990s, relatively less attention was paid to such effect which is partially due to the huge success of silicon‐based Flash memories.…”

“…[17] Theoretically, G 0 results from the contact resistance when a ballistic conductor with single transverse mode is sandwiched between two conductive pads. Historically, quantum conductance was first discovered in the 2D electron gas system of a GaAs-AlGaAs heterostructure at 0.6 K by van Wees et al in 1988, [19] and then in various metal nanowires [20][21][22] or quantum point contacts constructed by scanning tunneling microscope, [23][24][25] mechanically controllable break junction technique, [26,27] electrochemical deposition, [28,29] and etc. This will naturally result in the existence of some contact resistance, though the ballistic conductor itself has zero resistance.…”

Ultralow‐Power Atomic‐Scale Tin Transistor with Gate Potential in Millivolt

“…It has been demonstrated that the conductance of the tin point‐contact as a state variable can compete with the thermal noise bath at room temperature. Furthermore, the inner resistance of metallic atomic‐scale transistors is ≤ 12.9 kΩ, [ 12,14 ] much less than that of molecular electronic devices (in decades MΩ). [ 43 ]…”

“…[ 10 ] In this spirit, we have introduced atomic‐scale metallic transistors operated with a novel fundamental switching paradigm. [ 11–15 ]…”

“…[10] In this spirit, we have introduced atomicscale metallic transistors operated with a novel fundamental switching paradigm. [11][12][13][14][15] This paper demonstrates an atomic-scale tin transistor operated with an electrochemical potential applied to a gate. The required switching potential can be as low as 2.5 mV in magnitude, which is much lower than the minimal level on the supply voltage of a CMOS digital logic circuit set by Landauer's limit: [16] V DD ≥ 2(ln2)k B Te −1 = 35.8 mV, where k B is Boltzmann constant, T = 300 K, and e the electron charge, [17,18] and even smaller than the "action potentials" of neuron fire (−20−100 mV) in magnitude.…”