Electronic properties of novel 6 K superconductor LiFeP in comparison with LiFeAs from first principles calculations

Shein, I. R.; Ivanovskiĭ, A. L.

doi:10.1016/j.ssc.2009.10.021

Cited by 28 publications

(15 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The obtained Fermi surfaces ( Fig. 4) are similar to previous calculations [35]. Although angleresolved photoemission results have suggested quite different Fermi surfaces with no interband nesting in LiFeAs [33], more recent bulk measurements of dHvA oscillations reveal quasi-nested hole and electron sheets [37] in a good agreement with the calculations.…”

supporting

confidence: 88%

“…In LiFeAs, antiferromagnetic fluctuations have been observed [26,27] and fully gapped superconductivity has been demonstrated by several experiments [28][29][30][31][32][33], but no information has been reported for the pairing state in LiFeP. Bandstructure calculations show that the two materials exhibit similar Fermi surface shapes [34,35]; quasi-cylindrical hole sheets near the zone center and two warped electron sheets near the zone corner.Here we report on precision measurements of the magnetic penetration depth λ(T ) in single crystals, which demonstrate a nodal gap state in LiFeP in sharp contrast to the nodeless state in LiFeAs. Our analysis based on accumulated λ(T ) data in the 1111, 122, and 111 series of superconductors, indicates that the nodal state is induced when h P n is below a threshold value.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Nodeless Versus Nodal Order Parameters in LiFeAs and LiFeP

Hashimoto

2013

Non-Universal Superconducting Gap Structure in Iron-Pnictides Revealed by Magnetic Penetration Depth Measurements

View full text Add to dashboard Cite

High-precision measurements of magnetic penetration depth λ in clean single crystals of LiFeAs and LiFeP superconductors reveal contrasting low-energy quasiparticle excitations. In LiFeAs the low-temperature λ(T ) shows a flat dependence indicative of a fully gapped state, which is consistent with previous studies. In contrast, LiFeP exhibits a T -linear dependence of superfluid density ∝ λ −2 , indicating a nodal superconducting order parameter. A systematic comparison of quasiparticle excitations in the 1111, 122, and 111 families of iron-pnictide superconductors implies that the nodal state is induced when the pnictogen height from the iron plane decreases below a threshold value of ∼ 1.33Å.There is growing evidence that the superconducting gap structure is not universal in the iron-based superconductors [1]. In certain materials such as optimally doped (Ba,K)Fe 2 As 2 and Ba(Fe,Co) 2 As 2 , strong evidence for the fully gapped superconducting state has been observed from several low-energy quasiparticle excitation probes including magnetic penetration depth [2, 3] and thermal conductivity measurements [4,5]. In contrast, significant excitations at low temperatures due to nodes in the energy gap have been detected in several Fe-pnictide superconductors. These include LaFePO (T c = 6 K) [6-8], BaFe 2 (As,P) 2 (T c ≤ 31 K) [9-11], and KFe 2 As 2 (T c = 4 K) [12][13][14]. It is quite extraordinary that such distinct pairing states appear in closely related members of the same class of superconductors. To understand the mechanism of superconductivity in iron-based superconductors, it is essential to identify what determines nodal and nodeless states [15][16][17][18][19][20][21].Theories based on antiferromagnetic spin fluctuations suggest that the pnictogen height h P n above the iron plane (see Fig. 1(a)) is an important factor in determining the structure of the superconducting order parameter [16,[18][19][20]. Generally, h P n is much shorter for the P based iron-pnictides in comparison to their As counterparts, so a good test of the theory would be to systematically compare As and P based superconductors. Although this can be achieved in part in the BaFe 2 (As,P) 2 series, the fully As containing end member BaFe 2 As 2 is a nonsuperconducting antiferromagnet. The same is true for LaFeAsO which is the As analogue of the nodal superconductor LaFePO. Charge doping of the arsenides induces superconductivity, but also introduces disorder which complicates the identification of the pairing state.The 111 materials, LiFeAs [22,23] and LiFeP [24, 25] provide a unique route to study this problem as both materials are superconducting (T c ≈ 17 K and 4.5 K, respectively), nonmagnetic, and importantly very clean, with long electronic mean-free paths. In LiFeAs, antiferromagnetic fluctuations have been observed [26,27] and fully gapped superconductivity has been demonstrated by several experiments [28][29][30][31][32][33], but no information has been reported for the pairing state in LiFeP. Bandstructure calculations show t...

show abstract

supporting

confidence: 88%

mentioning

confidence: 99%

Nodeless Versus Nodal Order Parameters in LiFeAs and LiFeP

Hashimoto

2013

Non-Universal Superconducting Gap Structure in Iron-Pnictides Revealed by Magnetic Penetration Depth Measurements

View full text Add to dashboard Cite

show abstract

“…It was found that the order parameter Δ 1 = 1.5 meV in this compound is associated with hole car riers, while order parameter Δ 2 = 2.5 meV is associated with electron like charge carriers [15,16]. The two band nature of the order parameter in LiFeAs is also confirmed by heat capacity measurements [17] and by ab initio calculations [18]. The existence of two order parameters with different degrees of anisotropy leads to different physical properties [19].…”

mentioning

confidence: 63%

Vortex lattice in LiFeAs superconductor in the two-band Ginzburg-Landau model

Askerzade

2014

Tech. Phys.

View full text Add to dashboard Cite

show abstract

“…The highest temperature of doped SmFeAsO 1−x F x systems is 55 K for x = 0.2 [4,5]. The Fermi surface * E-mail: imasker@eng.ankara.edu.tr of SmFeAsO 1−x F x is formed by three concentric hole cylinders at the Γ point of Brilloun zone and a small hole cylinder near the zone boundary [6,7]. Many-band character of superconducting state of SmFeAsO 1−x F x was confirmed by ARPES [8] and de Haas-van Alphen experiments [9].…”

Section: Introductionmentioning

confidence: 99%

“…The main peculiarity of superconductivity in Fe-based compounds is related to the multiband character of state [4,6,7]. It is useful to note that the multiband Bardeen-Cooper-Schrieffer theory for Fe-based superconductors was suggested in recent studies [10,11].…”

Section: Introductionmentioning

confidence: 99%

Fluctuation conductivity in two-band superconductor SmFeAsO_0.8F_0.2

Askerzade

Askerbeyli

2015

Materials Science-Poland

View full text Add to dashboard Cite

In this study we have calculated the fluctuation conductivity near critical temperature of SmFeAsO 0.8 F 0.2 superconductor using two-band Ginzburg-Landau theory. It was illustrated that in the absence of external magnetic field, the two-band model reduced to a single effective band theory with modified temperature dependences. The calculations revealed three-dimensional character of fluctuations of conductivity in the new Fe-based superconductor SmFeAsO 0.8 F 0.2 . It has been shown that such a model is in good agreement with experimental data for this compound.

show abstract

Electronic properties of novel 6 K superconductor LiFeP in comparison with LiFeAs from first principles calculations

Cited by 28 publications

References 53 publications

Nodeless Versus Nodal Order Parameters in LiFeAs and LiFeP

Nodeless Versus Nodal Order Parameters in LiFeAs and LiFeP

Vortex lattice in LiFeAs superconductor in the two-band Ginzburg-Landau model

Fluctuation conductivity in two-band superconductor SmFeAsO_0.8F_0.2

Contact Info

Product

Resources

About

Electronic properties of novel 6 K superconductor LiFeP in comparison with LiFeAs from first principles calculations

Cited by 28 publications

References 53 publications

Nodeless Versus Nodal Order Parameters in LiFeAs and LiFeP

Nodeless Versus Nodal Order Parameters in LiFeAs and LiFeP

Vortex lattice in LiFeAs superconductor in the two-band Ginzburg-Landau model

Fluctuation conductivity in two-band superconductor SmFeAsO0.8F0.2

Contact Info

Product

Resources

About

Fluctuation conductivity in two-band superconductor SmFeAsO_0.8F_0.2