Anderson Mobility Gap Probed by Dynamic Coherent Backscattering

Area of Science:

• Condensed matter physics
• Materials science
• Wave propagation in disordered media

Background:

• Anderson localization describes the suppression of wave function propagation in disordered systems.
• Mesoglasses represent a class of strongly disordered materials with unique vibrational properties.
• Mobility gaps and edges are critical features in the spectral behavior of disordered systems.

Purpose of the Study:

• To investigate Anderson mobility gaps in the vibrational spectrum of three-dimensional mesoglasses.
• To utilize dynamic coherent backscattering to probe these spectral features.
• To determine the frequency-dependent localization length within these disordered materials.

Main Methods:

• Employing dynamic coherent backscattering (DCB) as the primary experimental technique.
• Comparing experimental DCB data with self-consistent theory of localization.
• Conducting transmission measurements for corroboration.

Main Results:

• Successfully studied Anderson mobility gaps in the vibrational spectrum of mesoglasses.
• Estimated the frequency-dependent localization (correlation) length across a wide spectral range.
• Observed distinct bands of diffuse transport and a mobility gap bounded by two mobility edges.

Conclusions:

• Dynamic coherent backscattering is effective for studying Anderson localization phenomena in mesoglasses.
• The estimated localization length provides crucial information about wave transport in disordered systems.
• Experimental findings align with theoretical predictions, validating the employed models.