A lower bound to the thermal diffusivity of insulators
Journal Article
·
· Journal of Physics. Condensed Matter
- PSL Research Univ., Paris (France); Univ. zu Köln, Koln (Germany)
- Stanford Univ., Stanford, CA (United States)
It has been known for decades that thermal conductivity of insulating crystals becomes proportional to the inverse of temperature when the latter is comparable to, or higher than, the Debye temperature. This behavior has been understood as resulting from Umklapp scattering among phonons. We put under scrutiny the magnitude of the thermal diffusion constant in this regime and find that it does not fall below a threshold set by the square of sound velocity times the Planckian time (τp = h/kBT). The conclusion, based on scrutinizing the ratio in cubic crystals with high thermal resistivity, appears to hold even in glasses where Umklapp events are not conceivable. Furthermore, explaining this boundary, reminiscent of a recently-noticed limit for charge transport in metals, is a challenge to theory.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC02-76SF00515
- OSTI ID:
- 1576517
- Alternate ID(s):
- OSTI ID: 23009270
- Journal Information:
- Journal of Physics. Condensed Matter, Journal Name: Journal of Physics. Condensed Matter Journal Issue: 40 Vol. 31; ISSN 0953-8984
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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