Electrodynamics of Amorphous Media at Low Temperatures

Abstract

Amorphous solids exhibit intrinsic, local structural transitions, that give rise to the well known quantum-mechanical two-level systems at low temperatures. We explain the microscopic origin of the electric dipole moment of these two-level systems: The dipole emerges as a result of polarization fluctuations between near degenerate local configurations, which have nearly frozen in at the glass transition. An estimate of the dipole's magnitude, based on the random first order transition theory, is obtained and is found to be consistent with experiment. The interaction between the dipoles is estimated and is shown to contribute significantly to the Grüneisen parameter anomaly in low $T$ glasses. In completely amorphous media, the dipole moments are expected to be modest in size despite their collective origin. In partially crystalline materials, however, very large dipoles may arise, possibly explaining the findings of Bauer and Kador, J. Chem. Phys. {\bf 118}, 9069 (2003).

Submitted for publication; April 27, 2005 version

References in corpus (4)

• Theory of Aging in Structural Glasses
• The Origin of the Boson Peak and the Thermal Conductivity Plateau in Low Temperature Glasses
• Barrier Softening near the onset of Non-Activated Transport in Supercooled Liquids: Implications for Establishing Detailed Connection between Thermodynamic and Kinetic Anomalies in Supercooled Liquids
• The Intrinsic Quantum Excitations of Low Temperature Glasses

Cited by in corpus (6)

• Theory of Structural Glasses and Supercooled Liquids
• Towards understanding two-level-systems in amorphous solids -- Insights from quantum circuits
• Theory of the Structural Glass Transition: A Pedagogical Review
• The "Tunneling Two-Level Systems" Model of the Low-Temperature Properties of Glasses: Are "Smoking-Gun" Tests Possible?
• Stress distribution and the fragility of supercooled melts
• Charge and momentum transfer in supercooled melts: Why should their relaxation times differ?