A chalcogenide glass ( ) has a measured low-temperature heat capacity below

PHYSICS · Multi-part · Fermi University Physics · Condensed Matter, Materials & Soft Matter · Crystal structure, bonding and diffraction · Lattice dynamics and thermal properties of solids

Solid State Physics, Ch Solids without a lattice: glasses and quasicrystals

Problem

A chalcogenide glass (As2S3\mathrm{As_2S_3}) has a measured low-temperature heat capacity C(T)=c1TC(T)=c_1T below 1 K1\,\mathrm{K}, with c1=0.30 μJ g−1 K−2c_1=0.30\,\mu\mathrm{J\,g^{-1}\,K^{-2}}, attributed, as for vitreous silica, to a flat density Pˉ\bar P (per unit mass, per unit energy interval) of two-level tunnelling splittings, via C=π26kB2Pˉ TC=\dfrac{\pi^2}{6}k_B^2\bar P\,T. ((a)) Find Pˉ\bar P in SI units (per gram per joule). ((b)) Predict CC at T=0.60 KT=0.60\,\mathrm{K}, ignoring the Debye (T3T^3) contribution, which is negligible at this temperature for a glass of this type.

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