Scientists Develop Single-Molecule Transistor Controlled by Mechanical Forces

The scientists employed a technique known as mechanically controllable break junction (MCBJ) to achieve this feat.

In a significant breakthrough in electronics, researchers at the S. N. Bose National Centre for Basic Sciences, an autonomous institute, have developed a unique transistor using single molecules, controlled by mechanical forces rather than traditional electrical signals. This innovation holds promise for advancements in quantum information processing, ultra-compact electronics, and sensing applications.

The scientists employed a technique known as mechanically controllable break junction (MCBJ) to achieve this feat. By using a piezoelectric stack, they meticulously broke a macroscopic metal wire to create a sub-nanometer gap precisely sized to accommodate a single molecule, such as ferrocene. This molecule, which features an iron atom sandwiched between two cyclopentadienyl (Cp) rings, exhibits altered electrical behavior when mechanically manipulated, showcasing the potential of mechanical gating in controlling electron transport at the molecular level.

Dr. Atindra Nath Pal and Biswajit Pabi, along with their team, discovered through experiments and calculations that the orientation of ferrocene molecules between silver electrodes significantly influences the transistor's performance. The device's electrical conductivity can be enhanced or diminished depending on the molecular orientation, highlighting the critical role of molecular geometry in transistor design.

Further research extended to the use of gold electrodes with ferrocene at room temperature, revealing a remarkably low resistance—nearly five times the quantum of resistance (around 12.9 kΩ) but significantly lower than the typical resistance of a molecular junction (around 1 MΩ). This finding suggests the potential for creating low-power molecular devices, which could lead to breakthroughs in various high-tech fields.