Negative thermal expansion of MgB$_{2}$ in the superconducting state and anomalous behavior of the bulk Grüneisen function

J. J. Neumeier; T. Tomita; M. Debessai; J. S. Schilling; P. W. Barnes; D. G. Hinks; J. D. Jorgensen

doi:10.1103/PhysRevB.72.220505

paper

Negative thermal expansion of MgB $_{2}$ in the superconducting state and anomalous behavior of the bulk Grüneisen function

arXiv:cond-mat/0510515 · doi:10.1103/PhysRevB.72.220505

Abstract

The thermal expansion coefficient $α$ of MgB $_{2}$ is revealed to change from positive to negative on cooling through the superconducting transition temperature $T_{c}$ . The Grüneisen function also becomes negative at $T_{c}$ followed by a dramatic increase to large positive values at low temperature. The results suggest anomalous coupling between superconducting electrons and low-energy phonons.

5 figures. submitted to Phys. Rev. Lett

Negative thermal expansion of MgB2​ in the superconducting state and anomalous behavior of the bulk Grüneisen function

Abstract

Negative thermal expansion of MgB $_{2}$ in the superconducting state and anomalous behavior of the bulk Grüneisen function