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Low-Temperature Heat Capacity Anomalies in Ordered and Disordered Phases of Normal and Deuterated Thiophene.

ABSTRACT: We measured the specific heat C_p of normal (C₄H₄S) and deuterated (C₄D₄S) thiophene in the temperature interval of 1 ≤ T, K ≤ 25. C₄H₄S exhibits a metastable phase II₂ and a stable phase V, both with frozen orientational disorder (OD), whereas C₄D₄S exhibits a metastable phase II₂, which is analogous to the OD phase II₂ of C₄H₄S and a fully ordered stable phase V. Our measurements demonstrate the existence of a large bump in the heat capacity of both stable and metastable C₄D₄S and C₄H₄S phases at temperatures of ∼10 K, which significantly departs from the expected Debye temperature behavior of C_p ≈ T³. This case study demonstrates that the identified low-temperature C_p anomaly, typically referred to as a "Boson-peak" in the context of glassy crystals, is not exclusive of disordered materials.

SUBMITTER: Miyazaki Y

PROVIDER: S-EPMC8594864 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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Low-Temperature Heat Capacity Anomalies in Ordered and Disordered Phases of Normal and Deuterated Thiophene.

Miyazaki Y Y Nakano M M Krivchikov A I AI Koroyuk O A OA Gebbia J F JF Cazorla C C Tamarit J Ll JL

The journal of physical chemistry letters 20210224 8

We measured the specific heat Cp of normal (C4H4S) and deuterated (C4D4S) thiophene in the temperature interval of 1 ≤ T, K ≤ 25. C4H4S exhibits a metastable phase II2 and a stable phase V, both with frozen orientational disorder (OD), whereas C4D4S exhibits a metastable phase II2, which is analogous to the OD phase II2 of C4H4S a ...[more]

PMID: 33625859

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