Interfacial thermal conduction and negative temperature jump in one-dimensional lattices

Area of Science:

• Condensed Matter Physics
• Statistical Mechanics
• Materials Science

Background:

• Thermal boundary resistance, or Kapitza resistance, is crucial for heat dissipation in nanostructured materials.
• Understanding heat transport at interfaces requires atomic-scale insights into lattice dynamics.

Purpose of the Study:

• Investigate thermal boundary conduction in 1D harmonic and $\phi^4$ lattices.
• Analyze heat flux and temperature jump at interfaces to understand Kapitza resistance.
• Explore anomalous phenomena like negative temperature jumps and nonlinear thermal responses.

Main Methods:

• Theoretical calculations and molecular dynamics simulations.
• Analysis of heat current and temperature profiles across interfaces.
• Modeling interfaces with gradually changing spring constants.

Main Results:

• Heat current is proportional to the square of coupling strength in the weak coupling regime for both harmonic and anharmonic models.
• A negative temperature jump was observed between interfacial particles in specific parameter regimes.
• Nonlinear response of boundary temperature jump to applied temperature difference in $\phi^4$ lattices.

Conclusions:

• The negative temperature jump persists even with a gradual interface model, suggesting a robust phenomenon.
• Numerical determination of local equilibrium at the interface is challenging due to near-Gaussian velocity distributions.
• The study provides atomic-scale understanding of interfacial thermal transport and Kapitza resistance.