Large Low Temperature Specific Heat in Pyrochlore Bi$_2$Ti$_2$O$_7$

Brent C. Melot; Ronald Tackett; Jim O'Brien; Andrew L. Hector; Gavin Lawes; Ram Seshadri; Arthur P. Ramirez

doi:10.1103/PhysRevB.79.224111

paper

Large Low Temperature Specific Heat in Pyrochlore Bi $_{2}$ Ti $_{2}$ O $_{7}$

arXiv:0904.1582 · doi:10.1103/PhysRevB.79.224111

Abstract

Both amorphous and crystalline materials frequently exhibit low temperature specific heats in excess of what is predicted using the Debye model. The signature of this excess specific heat is a peak observed in $C / T^{3}$ \textit{versus} $T$ . To understand the curious absence of long-range ordering of local distortions in the crystal structure of pyrochlore Bi $_{2}$ Ti $_{2}$ O $_{7}$ , we have measured the specific heat of crystalline Bi $_{2}$ Ti $_{2}$ O $_{7}$ and related compounds. We find that the peak in $C / T^{3}$ versus $T$ in Bi $_{2}$ Ti $_{2}$ O $_{7}$ falls at a substantially lower temperature than other similar compounds, consistent with the presence of disorder. This thermodynamic evidence for disorder in crystalline Bi $_{2}$ Ti $_{2}$ O $_{7}$ is consistent with quenched configurational disorder among Bi lone pairs produced by geometrical frustration, which could represent a possible realization of "charge ice".

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Large Low Temperature Specific Heat in Pyrochlore Bi $_{2}$ Ti $_{2}$ O $_{7}$

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Large Low Temperature Specific Heat in Pyrochlore Bi2​Ti2​O7​

Abstract

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Cited by in corpus (13)

Large Low Temperature Specific Heat in Pyrochlore Bi $_{2}$ Ti $_{2}$ O $_{7}$