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arXiv · 1804.00723

Nodeless superconductivity in type-II Dirac semimetal PdTe2: low-temperature London penetration depth and symmetry analysis

Serafim Teknowijoyo·Na Hyun Jo·Mathias S. Scheurer·M. A. Tanatar·Kyuil Cho·S. L. Bud'ko·Peter P. Orth·P. C. Canfield·R. Prozorov
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Abstract

Superconducting gap structure was probed in type-II Dirac semimetal PdTe$_2$ by measuring the London penetration depth using tunnel diode resonator technique. At low temperatures, the data for two samples are well described by weak coupling exponential fit yielding $λ(T=0)=230$~nm as the only fit parameter at a fixed $Δ(0)/T_c\approx 1.76$, and the calculated superfluid density is consistent with a fully gapped superconducting state characterized by a single gap scale. Electrical resistivity measurements for in-plane and inter-plane current directions find very low and nearly temperature-independent normal- state anisotropy. The temperature dependence of resistivity is typical for conventional phonon scattering in metals. We compare these experimental results with expectations from a detailed theoretical symmetry analysis and reduce the number of possible superconducting pairing states in PdTe$_2$ to only three nodeless candidates: a regular, topologically trivial, $s$-wave pairing, and two distinct odd-parity triplet states that both can be topologically non-trivial depending on the microscopic interactions driving the superconducting instability.

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Serafim Teknowijoyo, Na Hyun Jo, Mathias S. Scheurer, M. A. Tanatar, Kyuil Cho, S. L. Bud'ko, Peter P. Orth, P. C. Canfield, R. Prozorov. 2018-04-02. Nodeless superconductivity in type-II Dirac semimetal PdTe2: low-temperature London penetration depth and symmetry analysis. https://doi.org/10.1103/physrevb.98.024508

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