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Field-induced structural aging in glasses at ultralow temperatures
1Department of Physics, Stanford University, Stanford, California 94305-4060, USA.
Physical Review Letters
|October 4, 2003
Summary
Researchers studied dielectric response in Mylar and BK7 glasses at millikelvin temperatures. A new mechanism, beyond the tunneling model, explains the observed excess dielectric response, suggesting bias-induced structural changes.
Area of Science:
- Condensed matter physics
- Dielectric properties of amorphous solids
Background:
- Nonequilibrium dielectric response in glasses is complex.
- Existing models, like the tunneling model, partially explain decay dynamics.
Purpose of the Study:
- To investigate the excess dielectric response in Mylar and BK7 glasses.
- To refine existing models for describing long-time decay phenomena.
Main Methods:
- Nonequilibrium experiments applying a strong electric bias field.
- Measurements of excess dielectric response at millikelvin temperatures.
Main Results:
- Observed long-time decays in dielectric response for both Mylar and BK7.
- A modified model, incorporating an additional mechanism, successfully describes the data for both glasses.
- Identified temperature-independent decay times for the excess dielectric response.
Conclusions:
- The tunneling model alone is insufficient for BK7 glass.
- Bias field-induced structural rearrangements of tunneling states, decaying via quantum tunneling, represent a novel mechanism.
- This new mechanism provides a comprehensive explanation for the observed dielectric behavior in both Mylar and BK7 glasses.