Time-resolved X-ray diffraction investigation of the modified phonon dispersion in InSb nanowires

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Reduced heat conductivity in nanowires is a critical challenge for thermal management applications.
• Understanding phonon behavior is key to controlling thermal transport in nanostructures.

Purpose of the Study:

• To investigate the phonon dispersion in indium antimonide (InSb) nanowires.
• To identify the origin of reduced heat conductivity in these nanowires.

Main Methods:

• Time-resolved X-ray diffraction was employed to measure phonon dispersion.
• Phonon dispersion was analyzed for 50 nm diameter InSb (111) nanowires.

Main Results:

• The sound speed in InSb nanowires was measured at 2880 m/s, significantly lower than bulk InSb (3880 m/s) and classical thin rod theory (3600 m/s).
• A 35% reduction in the C44 elastic constant was observed compared to the bulk material.

Conclusions:

• The reduced sound speed in InSb nanowires is attributed to a significant decrease in the C44 elastic constant.
• This modification of the C44 elastic constant is the primary cause of the diminished heat conductivity in InSb nanowires.