Abstract:The superconducting film of (Li 1-x Fe x )OHFeSe is reported for the first time.The thin film exhibits a small in-plane crystal mosaic of 0. Moreover, a large critical current density (J c ) of a value over 0.5 MA/cm 2 is achieved at ~20 K. Such a (Li 1-x Fe x )OHFeSe film is therefore not only important to the fundamental research for understanding the high-T c mechanism, but also promising in the field of high-T c superconductivity application, especially in high-performance electronic devices and large scie… Show more
“…Sharp transition was reproduced for several small pieces (approximately 2×2 mm 2 ) of thin films of the same batch and indicates that the sample is homogeneous. The T c , obtained from the onset temperature of diamagnetism, of optimal (Li 1−x Fe x )OHFeSe films is 42 K. The transition width (10 to 90 % of the full signal) is less than 2 K. The film thickness is on the order of 100 nm as reported in Ref 27. .…”
We studied the electronic Raman spectra of (Li1−xFex)OHFeSe as a function of light polarization and temperature. In the B1g spectra alone we observe the redistribution of spectral weight expected for a superconductor and two well-resolved peaks below Tc. The nearly resolution-limited peak at 110 cm −1 (13.6 meV) is identified as a collective mode. The peak at 190 cm −1 (23.6 meV) is presumably another collective mode since the line is symmetric and its energy is significantly below the gap energy observed by single-particle spectroscopies. Given the experimental band structure of (Li1−xFex)OHFeSe, the most plausible explanations include conventional spin-fluctuation pairing between the electron bands and the incipient hole band and pairing between the hybridized electron bands. The absence of gap features in A1g and B2g symmetry favors the second case. Thus, in spite of various differences between the pnictides and chalcogenides, this Letter demonstrates the proximity of pairing states and the importance of band structure effects in the Fe-based compounds.
“…Sharp transition was reproduced for several small pieces (approximately 2×2 mm 2 ) of thin films of the same batch and indicates that the sample is homogeneous. The T c , obtained from the onset temperature of diamagnetism, of optimal (Li 1−x Fe x )OHFeSe films is 42 K. The transition width (10 to 90 % of the full signal) is less than 2 K. The film thickness is on the order of 100 nm as reported in Ref 27. .…”
We studied the electronic Raman spectra of (Li1−xFex)OHFeSe as a function of light polarization and temperature. In the B1g spectra alone we observe the redistribution of spectral weight expected for a superconductor and two well-resolved peaks below Tc. The nearly resolution-limited peak at 110 cm −1 (13.6 meV) is identified as a collective mode. The peak at 190 cm −1 (23.6 meV) is presumably another collective mode since the line is symmetric and its energy is significantly below the gap energy observed by single-particle spectroscopies. Given the experimental band structure of (Li1−xFex)OHFeSe, the most plausible explanations include conventional spin-fluctuation pairing between the electron bands and the incipient hole band and pairing between the hybridized electron bands. The absence of gap features in A1g and B2g symmetry favors the second case. Thus, in spite of various differences between the pnictides and chalcogenides, this Letter demonstrates the proximity of pairing states and the importance of band structure effects in the Fe-based compounds.
“…The next thin film presented here is (Li,Fe)OHFeSe (2 a = 50 µm, 2 b = 20 nm) where the raw J c (sf, T ) data reported by Huang et al . 25 is shown in Fig. 5.…”
Section: Resultsmentioning
confidence: 99%
“…For a fit of J c (sf, T ) using Eqs 7–11, we take into account measurements of the in-plane coherence length ξ ab (0) = 2.0 nm 25,47 and λ ab (0) = 280 nm 29 , which give the Ginzburg-Landau parameter as κ c = 140. The electron mass anisotropy for this compound is γ = 10 29 .Figure 5BCS fits to the experimental J c (sf, T ) data 25 and λ( T ) calculated from Eqs 7–11 for a (Li,Fe)OHFeSe thin film (2 a = 50 µm, 2 b = 20 nm) assuming a p -wave polar A ⊥ l model, κ c = 140 and γ = 10. Derived parameters are: T c = 41.34 ± 0.08 K, Δ(0) = 11.2 ± 0.4 meV, Δ C / C = 1.87 ± 0.03, λ(0) = 360 ± 4 nm, 2Δ(0)/k B T c = 6.3 ± 0.2.…”
Section: Resultsmentioning
confidence: 99%
“…BCS fits to the experimental J c (sf, T ) data 25 and λ( T ) calculated from Eqs 7–11 for a (Li,Fe)OHFeSe thin film (2 a = 50 µm, 2 b = 20 nm) assuming a p -wave polar A ⊥ l model, κ c = 140 and γ = 10. Derived parameters are: T c = 41.34 ± 0.08 K, Δ(0) = 11.2 ± 0.4 meV, Δ C / C = 1.87 ± 0.03, λ(0) = 360 ± 4 nm, 2Δ(0)/k B T c = 6.3 ± 0.2.…”
Section: Resultsmentioning
confidence: 99%
“…All c -axis oriented thin films for which we re-analyse results herein demonstrate a single band p -wave polar A ⊥ l case as our own NdFeAs(O,F) film. These samples are:Single atomic layer FeSe film with T c > 100 K 23 ;FeSe 0.5 Te 0.5 thin film with T c = 13 K 24 ;(Li,Fe)OHFeSe thin film with T c = 42.2 K 25 ;Co-doped BaFe 2 As 2 thin film with T c = 21 K 26 ;P-doped BaFe 2 As 2 thin film with T c = 29 K 27 ;We also analyse temperature dependent superfluid density, ρ s ( T ), for several bulk superconductors:LaFePO single crystal with T c = 29 K 28 ;(Li 0.84 Fe 0.16 )OHFe 0.98 Se single crystal with T c = 42.5 K 29 ;Rb 0.77 Fe 1.61 Se 2 single crystal with T c = 35.2 K 30 ;K 0.74 Fe 1.66 Se 2 single crystal with T c = 32.5 K 30 ;Type-II Weyl semimetal T d -MoTe 2 with T c = 1.48–2.75 K 31 .…”
The possibility of p-wave pairing in superconductors has been proposed more than five decades ago, but has not yet been convincingly demonstrated. One difficulty is that some p-wave states are thermodynamically indistinguishable from s-wave, while others are very similar to d-wave states. Here we studied the self-field critical current of NdFeAs(O,F) thin films in order to extract absolute values of the London penetration depth, the superconducting energy gap, and the relative jump in specific heat at the superconducting transition temperature, and find that all the deduced physical parameters strongly indicate that NdFeAs(O,F) is a bulk p-wave superconductor. Further investigation revealed that single atomic layer FeSe also shows p-wave pairing. In an attempt to generalize these findings, we re-examined the whole inventory of superfluid density measurements in iron-based superconductors and show quite generally that single-band weak-coupling p-wave superconductivity is exhibited in iron-based superconductors.
Chemical engineering tailors functional materials to meet the demands of physical and chemical properties, accelerating materials discovery and design in a multidisciplinary field. However, stereotyped synthetic paradigms in physical and chemical approaches obstruct the effective integration of multiple advantages of respective materials exploration methods. Solid state reaction is often considered separately with wet chemistry synthesis route, such as film growth using physical vapor deposition and hydrothermal methods. Here, the controlled growth of FeSe thin films by physical deposition techniques followed by the chemical engineering to create heterogenous interface in FeSe films via a solution‐based environment is demonstrated. The two‐step route allows an expanded crystal structure and enhanced superconducting transition temperature from 3.6 to 38 K, providing a new strategy to design functional hybrid materials.
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