Defects&TLSs and glass transition
theory
- KT transition as a reason for non-Arrhenius behaviour?
2022 Theory of melting of glasses Chandra M. Varma
motivation - specific heat peak at melting temperature is closely connected with the density of LEEs see also as linear-in-temperature specific heat at VERY low temperatures. Therefore LEAKING (with or without tunneling). Both phenomena, peak at Tg and γ∗T of specific heat at glass temperature and low tempreatures correspondingly, occur concurrently
- 2019 Nussinov-Weingarter
already topological-KT transition
Third, the measured T3 specific heat is larger than that given by the elastic constants - the original TLM has nothing to say about this.
The change in the so called excess T3 specific heat with density is identical to that of the linear in T heat capacity
HUGE peak for crystal but noticeable peak for glass - features of the specific heat
open questions
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a) since TG∼100−1000K, for defect-freezing-out transition the defect size needs to be ξG∼10A=10−7cm
1-order of magnitude ---BPeak energy scale of defect is (30k), but glass temperature (300k)
crossover temparature TQ∼10K is by KT relation TQ≈12ρs∼γ2ρc2tξ3
10K∼10−15erg∼10−3eV∼ℏcR0
10−15erg=10−27erg∗s∗4∗105cm/s50A, so R0∼50A
IF γ∼6.3eV and ρc2tξ3≈2(g/cm3)421010(cm/s)2125∗10−21cm3≈4∗10−8erg=40,000eV,
so TQ∼10−3eV∼10K
- b) RG equations to be checked/reproduced?
2022 Anomalous Elasticity and Emergent Dipole Screening in Three-Dimensional Amorphous Solids
experimental links - forcing out of "universal"/natural regime
- 2015 Two-Level Systems in Evaporated Amorphous Silicon D.R. Queen, X. Liu, J. Karel, H.C. Jacks, T.H. Metcalf, F. Hellman
- 2014 Suppression of tunneling two-level systems in ultrastable glasses of indomethacin Tomás Pérez-Castañeda, Cristian Rodríguez-Tinoco, Javier Rodríguez-Viejo, and Miguel A. Ramos
experiments around "universal regime"
How Universal are the Low Temperature Acoustic Properties of Glasses? - 1988 - Berret-Meissner