Muon spin rotation study of the topological superconductor 
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Leng, Haiyan; Cherian, Dona; Huang, Yue-Kai; Orain, Jean-Christophe; Amato, A.; Visser, A. de

doi:10.1103/physrevb.97.054503

Cited by 17 publications

(13 citation statements)

References 43 publications

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“…Having in mind 100% SC volume fraction, the effective penetration depth, λ eff , at zero temperature is found to be 930(10) nm. Such a high value of λ eff was also estimated previously for other sister compounds, namely Cu and Sr doped Bi 2 Si 3 [24,50,51]. In view of the short coherence length and relatively large mean-free path l ∼ 50 nm [20], we can assume that Nb 0.25 Bi 2 Se 3 lies close to the clean limit.…”

Section: Resultssupporting

confidence: 80%

Time-reversal invariant and fully gapped unconventional superconducting state in the bulk of the topological compound Nb0.25Bi2Se3

et al. 2020

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Recently, the niobium (Nb) doped topological insulator Bi 2 Se 3 , in which the finite magnetic moments of the Nb atoms are intercalated in the van der Waals gap between the Bi 2 Se 3 layers, has been shown to exhibit both superconductivity with T c 3 K and topological surface states. Here we report on muon spin rotation experiments probing the temperature and field dependence of effective magnetic penetration depth λ eff (T) in the layered topological superconductor candidate Nb 0.25 Bi 2 Se 3. The exponential temperature dependence of λ −2 eff (T) at low temperatures suggests a fully gapped superconducting state in the bulk with the superconducting transition temperature T c = 2.9 K and the gap to T c ratio 2 /k B T c = 3.95(19). We also reveal that the ratio T c /λ −2 eff is comparable to those of unconventional superconductors, which hints at an unconventional pairing mechanism. Furthermore, time-reversal symmetry breaking was excluded in the superconducting state with sensitive zero-field μSR experiments. We hope the present results will stimulate theoretical investigations to obtain a microscopic understanding of the relation between superconductivity and the topologically nontrivial electronic structure of Nb 0.25 Bi 2 Se 3 .

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Section: Resultssupporting

confidence: 80%

Time-reversal invariant and fully gapped unconventional superconducting state in the bulk of the topological compound Nb0.25Bi2Se3

et al. 2020

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“…This value will be reduced if the assumption of a fully superconducting sample is removed. Such a high value of λ ef f was also estimated previously for other sister compounds namely Cu and Sr doped Bi 2 Si 3 24,49,50 . In view of the short coherence length and relatively large l 20 , we can assume that Nb 0.25 Bi 2 Se 3 lies close to the clean limit.…”

Section: Figuresupporting

confidence: 83%

Time-reversal invariant and fully gapped unconventional superconducting state in the bulk of the topological Nb0.25Bi2Se3

Das,

Kobayashi,

Smylie

et al. 2020

Preprint

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Recently, the niobium (Nb)-doped topological insulator Bi2Se3, in which the finite magnetic moments of the Nb atoms are intercalated in the van der Waals gap between the Bi2Se3 layers, has been shown to exhibit both superconductivity with Tc 3 K and topological surface states. Here we report on muon spin rotation experiments probing the temperature-dependent of effective magnetic penetration depth λ ef f (T ) in the layered topological superconductor candidate Nb0.25Bi2Se3. The exponential temperature dependence of λ −2 ef f (T ) at low temperatures suggests a fully gapped superconducting state in the bulk with the superconducting transition temperature Tc = 2.9 K and the gap to Tc ratio 2∆/kBTc = 3.95(19). We also revealed that the ratio Tc/λ −2 ef f is comparable to those of unconventional superconductors, which hints at an unconventional pairing mechanism. Furthermore, time reversal symmetry breaking was excluded in the superconducting state with sensitive zero-field µSR experiments. We hope the present results will stimulate theoretical investigations to obtain a microscopic understanding of the relation between superconductivity and the topologically non-trivial electronic structure of Nb0.25Bi2Se3.

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“…Intriguingly, it has been suggested that topological insulators of the Bi 2 Se 3 family could also be turned into topological superconductors [8]. Bulk doping by Cu [9][10][11][12][13], Sr [14][15][16][17], and Nb [18][19][20][21][22][23][24][25][26] has indeed led to the observation of (not necessarily topological) superconductivity in these materials. The mechanism driving the superconductivity is widely thought to be metal intercalation in the van der Waals gap between the quintuple layers forming the Bi 2 Se 3 structure [9].…”

Section: Introductionmentioning

confidence: 99%

Structural and electronic inhomogeneity of superconducting Nb-doped Bi2Se3

et al. 2021

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The crystal structure, electronic structure, and transport properties of crystals with the nominal composition Nb 0.25 Bi 2 Se 3 are investigated. X-ray diffraction reveals that the as-grown crystals display phase segregation and contain major contributions of BiSe and the superconducting misfit layer compound (BiSe) 1.1 NbSe 2 . The inhomogeneous character of the samples is also reflected in the electronic structure and transport properties of different single crystals. Angle-resolved photoemission spectroscopy (ARPES) reveals an electronic structure that resembles poor-quality Bi 2 Se 3 with an ill-defined topological surface state. High-quality topological surface states are instead observed when using a highly focused beam size, i.e., nanoARPES. While the superconducting transition temperature is found to vary between 2.5 and 3.5 K, the majority of the bulk single crystals does not exhibit a zero-resistance state suggesting filamentary superconductivity in the materials. Susceptibility measurements of the system together with the temperature dependence of the coherence length extracted from the upper critical field are consistent with conventional BCS superconductivity of a type II superconductor.

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Muon spin rotation study of the topological superconductor SrxBi2Se3

Cited by 17 publications

References 43 publications

Time-reversal invariant and fully gapped unconventional superconducting state in the bulk of the topological compound Nb0.25Bi2Se3

Time-reversal invariant and fully gapped unconventional superconducting state in the bulk of the topological compound Nb0.25Bi2Se3

Time-reversal invariant and fully gapped unconventional superconducting state in the bulk of the topological Nb0.25Bi2Se3

Structural and electronic inhomogeneity of superconducting Nb-doped Bi2Se3

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