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arXiv · 1808.00947

Excess speicific heat of the gapped sliding phonons in the incommensurate composite crystal Sr$_{14}$Cu$_{24}$O$_{41}$

Rabindranath Bag·Soumitra Hazra·R. N. Kini·Surjeet Singh
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Abstract

We show that low temperature specific heat (C$_p$) of the incommensurate chain-ladder system Sr$_{14}$Cu$_{24}$O$_{41}$ is enriched by the presence of a rather large excess contribution of non-magnetic origin. Diluted Al doping at the Cu site or annealing the crystal in an O$_2$ atmosphere suppresses this feature considerably. Using the THz time-domain spectroscopy, we show that the occurrence of excess specific heat is associated with the presence of very low-energy ($\sim$ 1 meV) gapped phonon modes that originate due to the sliding motion of oppositely charged mutually incommensurate chain and ladder layers.

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Rabindranath Bag, Soumitra Hazra, R. N. Kini, Surjeet Singh. 2018-08-03. Excess speicific heat of the gapped sliding phonons in the incommensurate composite crystal Sr$_{14}$Cu$_{24}$O$_{41}$. https://doi.org/10.1103/physrevb.99.054305

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