Decoding the phonon transport of structural lubrication at silicon/silicon interface

Area of Science:

• Tribology
• Materials Science
• Solid-State Physics

Background:

• Phonon transport mechanisms at structural lubrication interfaces remain unclear.
• Understanding interfacial phenomena is crucial for predicting friction and wear.

Purpose of the Study:

• To elucidate the role of phonon transport in friction at the Si/Si interface.
• To investigate the relationship between interfacial thermal resistance (ITR) and friction characteristics.

Main Methods:

• Experimental investigation of friction force under varying rotational angles, normal load, and temperature.
• Analysis of interfacial temperature differences and their correlation with contact commensurability.
• Examination of phonon transport pathways and energy dissipation mechanisms.

Main Results:

• A 90°-symmetry of friction force was observed at the Si/Si interface, independent of normal load and temperature.
• Incommensurate contacts showed significantly larger interfacial temperature differences due to higher ITR.
• Lower ITR in commensurate contacts facilitated more effective phonon energy dissipation.

Conclusions:

• Phonon transport dynamics directly influence frictional energy dissipation at structural interfaces.
• Contact commensurability dictates ITR and consequently friction behavior.
• The number of excited phonons correlates with the extent of frictional energy dissipation.