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SSCU Student Seminar
 
Name: Ms. Suchetana Bandyopadhyay
 
Title: Quantum Interference in Molecular Junctions
      Date & Time: Thursday, 19th February 2026 at 4.00 p.m. 
     Venue: Rajarshi Bhattacharyya Memorial  Lecture Hall, Chemical Sciences Building
Abstract:
Single-molecule junctions represent the ultimate limit of electronic miniaturization, where charge transport occurs through an individual molecule which is chemically or physically connected between two electrodes. After Aviram and Ratner had proposed the seminal theoretical framework , molecular junctions have served as a platform to explore fundamental charge transport mechanisms governed by molecular electronic structure and electrode–molecule coupling. Advance experimental techniques such as mechanically controllable break junctions (MCBJ) and scanning tunnelling microscopy (STM), together with theoretical formalisms based on Landauer transport and non-equilibrium Green’s functions, have enabled reliable measurement and modelling of conductance at the single-molecule level.
A central and defining feature of charge transport in single-molecule junctions is quantum interference (QI), which arises from the wave nature of electrons which are travelling through multiple molecular pathways. Constructive and destructive nature of interference, dictated by molecular topology, symmetry, and connectivity to electrodes, can strongly enhance or suppress conductance without altering molecular length or composition. Destructive quantum interference has been experimentally observed in cross-conjugated systems, meta-connected aromatic molecules, and σ–π coupled frameworks, leading to reduction in conductance. Conversely, molecular designs that promote constructive interference enable higher conductance and improved transport efficiency.
Recent research has expanded QI concepts beyond coherent charge transport to include the influence of vibronic coupling, electrochemical gating, and many-body interactions, revealing pathways to dynamically modulate interference effects by means of molecular topology. Quantum interference has also emerged as a key design principle for functional molecular devices, including high-performance thermoelectrics, molecular switches, and logic elements. quantum interference continues to be a cornerstone of modern single-molecule transport research by enabling precise control over electron flow through chemical structure alone, directly extending and enriching the foundational vision laid out by Ratner.
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