Superconducting density of states of PtPb4
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arXiv
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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866909709466861568 |
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| author | Talavera, Pablo García Moreno, Jose Antonio Herrera, Edwin Buzdin, Alexander I. Bud'ko, Sergey L. Canfield, Paul C. Guillamón, Isabel Suderow, Hermann |
| author_facet | Talavera, Pablo García Moreno, Jose Antonio Herrera, Edwin Buzdin, Alexander I. Bud'ko, Sergey L. Canfield, Paul C. Guillamón, Isabel Suderow, Hermann |
| contents | PtPb$_4$ is a type II superconductor with a bulk critical temperature $T_{c}\approx 3 $K and an upper critical field of $H_{c2}=0.36 $T. PtPb$_4$ is related to non-superconducting PtSn$_4$, which presents nodal arc states at the surface. Here we measure the superconducting density of states of PtPb$_4$ using millikelvin Scanning Tunneling Microscopy (STM). We observe a fully opened superconducting gap of $Δ=0.48$\ meV similar to expectations from Bardeen Cooper and Schrieffer (BCS) theory ($Δ_0=1.76k_BT_{c}=0.49 $meV). Measurements under magnetic fields applied perpendicular to the surface show a spatially inhomogeneous gap structure, presenting superconducting signatures at fields as high as 1.5 T, significantly above $H_{c2}=0.36 $T. On some locations we find that the superconducting density of states does not vanish above $T_{c}$. We can find signatures of a superconducting gap up to 5K. We discuss possible reasons for the observation of superconducting properties above $T_{c}$ and $H_{c2}$, emphasizing the role played by structural defects. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2507_21013 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Superconducting density of states of PtPb4 Talavera, Pablo García Moreno, Jose Antonio Herrera, Edwin Buzdin, Alexander I. Bud'ko, Sergey L. Canfield, Paul C. Guillamón, Isabel Suderow, Hermann Superconductivity Mesoscale and Nanoscale Physics Strongly Correlated Electrons PtPb$_4$ is a type II superconductor with a bulk critical temperature $T_{c}\approx 3 $K and an upper critical field of $H_{c2}=0.36 $T. PtPb$_4$ is related to non-superconducting PtSn$_4$, which presents nodal arc states at the surface. Here we measure the superconducting density of states of PtPb$_4$ using millikelvin Scanning Tunneling Microscopy (STM). We observe a fully opened superconducting gap of $Δ=0.48$\ meV similar to expectations from Bardeen Cooper and Schrieffer (BCS) theory ($Δ_0=1.76k_BT_{c}=0.49 $meV). Measurements under magnetic fields applied perpendicular to the surface show a spatially inhomogeneous gap structure, presenting superconducting signatures at fields as high as 1.5 T, significantly above $H_{c2}=0.36 $T. On some locations we find that the superconducting density of states does not vanish above $T_{c}$. We can find signatures of a superconducting gap up to 5K. We discuss possible reasons for the observation of superconducting properties above $T_{c}$ and $H_{c2}$, emphasizing the role played by structural defects. |
| title | Superconducting density of states of PtPb4 |
| topic | Superconductivity Mesoscale and Nanoscale Physics Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2507.21013 |