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arXiv · 1705.08054

Strong-Coupling Superconductivity in BaPd2As2 Induced by Soft Phonons in the ThCr2Si2-type Polymorph

Kazutaka Kudo·Yoshiaki Yamada·Takaaki Takeuchi·Takumi Kimura·Satoshi Ioka·Genta Matsuo·Yutaka Kitahama·Minoru Nohara
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Abstract

The specific heat of two polymorphs of BaPd2As2 was measured. The ThCr2Si2-type polymorph (space group I4/mmm, $D_{4h}^{17}$, No. 139) is a previously reported superconductor with a transition temperature Tc $\simeq$ 3.5 K, while the CeMg2Si2-type polymorph (P4/mmm, $D_{4h}^{1}$, No. 123) is a normal metal and does not exhibit superconductivity down to 1.8 K. Our results revealed that the ThCr2Si2-type has an anomalously low Debye temperature, indicative of soft phonons, compared to the CeMg2Si2-type. Moreover, a large specific-heat jump at Tc indicated that the superconductivity of ThCr2Si2-type is a strong-coupling type, which is likely derived from soft phonons.

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Kazutaka Kudo, Yoshiaki Yamada, Takaaki Takeuchi, Takumi Kimura, Satoshi Ioka, Genta Matsuo, Yutaka Kitahama, Minoru Nohara. 2017-05-23. Strong-Coupling Superconductivity in BaPd2As2 Induced by Soft Phonons in the ThCr2Si2-type Polymorph. https://doi.org/10.7566/jpsj.86.063704

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