Stark control of electrons along nanojunctions

Area of Science:

• Nanoscience and nanotechnology
• Quantum electronics
• Materials science

Background:

• Ultrafast control of nanoscale currents is crucial for next-generation nanoelectronics.
• Recent experiments show laser-induced currents in gold-silica-gold nanojunctions without bias voltage.
• The microscopic origin of these photoinduced currents is debated due to the non-equilibrium nature of the system.

Purpose of the Study:

• To elucidate the microscopic mechanism behind laser-induced phase-controllable currents in nanojunctions.
• To provide an intuitive explanation for experimentally observed phenomena.
• To validate theoretical models against experimental findings.

Main Methods:

• Atomistically detailed electronic transport simulations.
• Time-dependent non-equilibrium Green's function (TDNEGF) approach.
• Modeling of gold-silica-gold nanojunctions subjected to few-cycle laser pulses.

Main Results:

• Simulations successfully reproduced key experimental observations of photoinduced currents.
• A clear, intuitive picture of the current generation mechanism was established.
• The currents arise from asymmetric effective silica-metal coupling influenced by laser field amplitudes.

Conclusions:

• The study clarifies the origin of laser-induced currents in nanojunctions.
• Insights support the interpretation of related experiments.
• Advances the control of electrons in matter using ultrafast lasers for nanoelectronic applications.