Viscous Current-Induced Forces

Area of Science:

• Condensed Matter Physics
• Quantum Chemistry
• Materials Science

Background:

• Diatomic impurities in electron liquids experience forces from electronic currents.
• Understanding these forces is crucial for predicting impurity dynamics and material properties.

Purpose of the Study:

• To investigate the translational, vibrational, and rotational motion of diatomic impurities in an electron liquid under electronic current.
• To analyze the interplay between current-induced forces (electron wind) and electronic friction.
• To elucidate the role of dynamic exchange-correlation effects on impurity motion.

Main Methods:

• Linear response time-dependent density functional theory (TDDFT).
• Ehrenfest dynamics simulations.
• Solution of a system of linear algebraic equations.

Main Results:

• Identified coupling between center-of-mass and internal nuclear motion mediated by the electron liquid.
• Observed three distinct phases of motion: acceleration, stabilization, and deceleration.
• Quantified the significant contribution of dynamic exchange-correlation kernel to forces, especially at lower electron densities (up to 40% for Cs density in rotational regime).

Conclusions:

• The motion of diatomic impurities in electron liquids is complex, involving coupled degrees of freedom.
• Electronic friction and current-induced forces dictate the dynamic response.
• Dynamic exchange-correlation effects play a critical role in accurately describing impurity dynamics, particularly at lower metallic densities.