Gossamer high-temperature bulk superconductivity in FeSe

Синченко, А. А.; Grigoriev, P. D.; Орлов, А. П.; Frolov, A. V.; Шакин, А.; Чареев, Д. А.; Волкова, О. С.; Vasiliev, A. N.

doi:10.1103/physrevb.95.165120

Cited by 24 publications

(107 citation statements)

References 34 publications

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“…This can be the reason of such variety of dV/dI as for different PCs. Taking into account the huge anisotropy of resistivity of FeSe according to [18], it is not excluded that thermopower measured along the c-direction can have also different behavior and sign.…”

Section: Discussionmentioning

confidence: 99%

Superconducting gaps in FeSe studied by soft point-contact Andreev reflection spectroscopy

et al. 2017

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FeSe single crystals have been studied by soft point-contact Andreev-reflection spectroscopy. Superconducting gap features in the differential resistance dV /dI(V ) of point contacts such as a characteristic Andreev-reflection double-minimum structure have been measured versus temperature and magnetic field. Analyzing dV /dI within the extended two-gap Blonder-Tinkham-Klapwijk model allows to extract both the temperature and magnetic field dependence of the superconducting gaps. The temperature dependence of both gaps is close to the standard BCS behavior. Remarkably, the magnitude of the double-minimum structure gradually vanishes in magnetic field, while the minima position only slightly shifts with field indicating a weak decrease of the superconducting gaps. Analyzing the dV /dI(V ) spectra for 25 point contacts results in the averaged gap values ∆L = 1.8±0.4 meV and ∆S =1.0±0.2 meV and reduced values 2 ∆L /kBTc=4.2± 0.9 and 2 ∆S /kBTc=2.3±0.5 for the large (L) and small (S) gap, respectively. Additionally, the small gap contribution was found to be within tens of percent decreasing with both temperature and magnetic field. No signatures in the dV /dI spectra were observed testifying a gapless superconductivity or presence of even smaller gaps.

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Section: Discussionmentioning

confidence: 99%

Superconducting gaps in FeSe studied by soft point-contact Andreev reflection spectroscopy

et al. 2017

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“…From (16) it follows that there is a sign change of the order parameter between hole and electron pockets. Inserting then the values of |∆ h |, |∆ e | obtained from (14), (15), into (16), we arrive at…”

Section: Identical Hole Bandsmentioning

confidence: 99%

“…Interestingly, a recent quasiparticle interference (QPI) study of FeSe 11 has revealed that the ratio of the superconducting gap to the Fermi energy on the shallow electron band is very large ∆/E Fe ∼ 1 with similar ratios ∆/E F ≈ 0.6 being reported for FeSe x Te 1−x 7,12,13 . This has been followed up by observation of strong superconducting fluctuations in FeSe far above T c [14][15][16] . The large values of ∆/E F observed initially in FeSe have been interpreted 11 as a signature of a crossover from conventional Cooper pairing (BCS) to Bose-Einstein condensation (BEC) regime 17 .…”

Section: Introductionmentioning

confidence: 95%

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s+is superconductivity with incipient bands: Doping dependence and STM signatures

et al. 2017

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Motivated by the recent observations of small Fermi energies and comparatively large superconducting gaps, present also on bands not crossing the Fermi energy (incipient bands) in iron-based superconductors, we analyze the doping evolution of superconductivity in a four-band model across the Lifshitz transition including BCS-BEC crossover effects on the shallow bands. Similar to the BCS case, we find that with hole doping the phase difference between superconducting order parameters of the hole bands change from 0 to π through an intermediate s + is state, breaking time-reversal symmetry (TRS). The transition, however, occurs in the region where electron bands are incipient and chemical potential renormalization in the superconducting state leads to a significant broadening of the s + is region. We further present the qualitative features of the s + is state that can be observed in scanning tunneling microscopy (STM) experiments, also taking incipient bands into account.

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“…Наконец при T = T c весь объeм становится сверхпроводящим. Этот тип неоднородного развития сверхпроводящих свойств выше T c был назван Gossamer Superproductivity [9]. Он также может называться гетерогенной сверхпроводимостью.…”

Section: Introductionunclassified

Избыточная Проводимость Анизотропных Неоднородных Сверхпроводников При Температуре Выше Критической

Могилюк¹,

Григорьев²,

Кешарпу³

et al. 2019

Физика Твердого Тела

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The theoretical model of conductivity of a layered anisotropic normal metal containing small superconducting ellipsoidal granules with an arbitrary ratio of semiaxes is developed. Calculation data obtained under two simple approximations (self-consistent and Maxwell) are compared. The results may be applied in the analysis of the observed temperature dependence of the conductivity anisotropy in various anisotropic superconductors with the superconducting phase emerging in the form of isolated superconducting granules. The temperature dependence of the electric resistance along and across the conducting layers above and near the superconducting transition temperature is studied experimentally for bridge structures of a varying thickness. It is demonstrated that this resistance and even the effective superconducting transition temperature depend strongly on the bridge thickness (i.e., the number of layers through which the electric current flows). Note that significant differences were observed only for the resistance across the layers.

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Gossamer high-temperature bulk superconductivity in FeSe

Cited by 24 publications

References 34 publications

Superconducting gaps in FeSe studied by soft point-contact Andreev reflection spectroscopy

Superconducting gaps in FeSe studied by soft point-contact Andreev reflection spectroscopy

s+is superconductivity with incipient bands: Doping dependence and STM signatures

Избыточная Проводимость Анизотропных Неоднородных Сверхпроводников При Температуре Выше Критической

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