A coherent nanomechanical oscillator driven by single-electron tunnelling

Area of Science:

• Quantum mechanics
• Condensed matter physics
• Nanotechnology

Background:

• Single-electron transistors (SETs) in nanomechanical resonators push electron-phonon coupling limits.
• Electron tunneling in SETs causes backaction, perturbing mechanical states stochastically.
• Theoretical predictions suggest coherent mechanical oscillations under strong coupling.

Purpose of the Study:

• To experimentally verify the prediction of self-sustaining coherent mechanical oscillations.
• To investigate the laser-like analogies in a driven electromechanical system.
• To explore feedback mechanisms for controlling mechanical oscillations.

Main Methods:

• Real-time measurements of a vibrating carbon nanotube transistor.
• Utilizing a single-electron transistor as a gain medium and the resonator as a phonon cavity.
• Applying electrical bias to pump the system.

Main Results:

• Confirmed self-sustaining coherent mechanical oscillations.
• Demonstrated laser-like behaviors: injection locking and frequency narrowing via feedback.
• Observed classical squeezing through anharmonicity.

Conclusions:

• The study validates predictions of coherent mechanical oscillations in SET-resonator systems.
• The system functions as an unconventional electromechanical oscillator with laser analogies.
• This work opens avenues for novel quantum electromechanical devices and feedback control strategies.