Disorder-induced far infrared absorption in amorphous materials

Abstract In a variety of amorphous materials, the far infrared and microwave absorption (3–3000 GHz or 0.1–100 cm−1) is orders of magnitude greater than that observed in corresponding crystalline materials. This absorption is temperature independent and rises with frequency as νβ (β ≲ 2). The magnitude of the absorption correlates with the density of states inferred from the T3 term in specific heat, and is interpreted as due to a disorder-induced coupling of the far infrared radiation to a density of low frequency Debye modes in the amorphous solids.

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