Exact Analytic Formula for Conductance Predicting a Tunable Sommerfeld–Arrhenius Thermal Transition within a Single‐Step Tunneling Mechanism in Molecular Junctions Subject to Mechanical Stretching

• Published in: Advanced theory and simulations Vol. 5; no. 7
• Main Author: Bâldea, Ioan
• Format: Journal Article
• Language: English
• Published: 01.07.2022
• Subjects: charge transport; conductance; electron tunneling; molecular junctions; thermal effects
• ISSN: 2513-0390; 2513-0390
• DOI: 10.1002/adts.202200158

It is shown that the conductance G of molecular tunnel junctions wherein the charge transport is dominated by a single energy level can be expressed in closed analytic form which is exact and valid at arbitrary temperature T and model parameter values. On this basis, it is shown that the single‐step tunneling mechanism is compatible with a continuous thermal transition from a weakly T‐dependent G at low T (Sommerfeld regime) to a nearly exponential 1/T$1/T$‐dependent G at high T (Arrhenius‐like regime). This Sommerfeld–Arrhenius transition can be observed in real molecular junctions and can be continuously tuned, for example, via mechanical stretching. The exact formula expressing the conductance of a tunneling junction as a function of temperature T deduced here in closed analytic form in terms of elementary function predicts a thermal transition from a nearly independent T (Sommerfeld) regime to a nearly exponential (Arrhenius) regime that can be continuously tuned, for example, via mechanical stretching or molecular orbital gating.