Nanoscale and Element-Specific Lattice Temperature Measurements Using Core-Loss Electron Energy-Loss Spectroscopy.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Spectroscopy

Background:

• Measuring local temperatures at the nanoscale, especially in complex materials, is difficult.
• Spectroscopic methods like electron energy-loss spectroscopy (EELS) can detect temperature changes but require careful interpretation.

Purpose of the Study:

• To investigate the potential of core-loss spectroscopy for nanoscale thermometry.
• To compare the accuracy of core-loss thermometry with plasmon energy expansion thermometry (PEET).

Main Methods:

• Ab initio modeling using density functional theory (DFT) and the Bethe-Salpeter equation.
• Scanning transmission electron microscopy (STEM) to analyze Si L2,3 edge redshift and plasmon energy shifts.
• Comparison of core-loss thermometry with PEET for semiconductor samples.

Main Results:

• Core-loss redshift is attributed to bandgap reduction via electron-phonon renormalization.
• Core-loss thermometry provides more accurate thermal expansion modeling in semiconductors than PEET.
• Core-loss thermometry offers elemental specificity and potential for smaller length scales.

Conclusions:

• Core-loss thermometry is a promising, accurate technique for nanoscale temperature measurements in semiconductors.
• It offers advantages over PEET in complex materials and interfaces, especially when dielectric properties are unknown.
• This method enables elemental-specific nanoscale heating analysis in multicomponent systems.