Two distinct superconducting pairing states divided by the nematic end point in FeSe
 
 1−
 x
 
 S
 
 x

Hanaguri, T.; Iwaya, Katsuya; Kohsaka, Y.; Machida, T.; Watashige, Tatsuya; Kasahara, S.; Shibauchi, T.; Matsuda, Yuji

doi:10.1126/sciadv.aar6419

Cited by 99 publications

(119 citation statements)

References 51 publications

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…The striking difference in magnetotransport behaviour between the nematic and tetragonal phase in FeSe 1−x S x can have significant implications on what kind of superconductivity is stabilized inside and outside the nematic phase as different pairing channels may be dominant in different regions, as found experimentally [18,19]. Linear resistivity found at low temperatures inside the nematic state is present in the region where spin-fluctuations are likely to be present.…”

Section: Resultsmentioning

confidence: 85%

See 1 more Smart Citation

Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1−xSx

Bristow

Reiss

Haghighirad

et al. 2020

Phys. Rev. Research

View full text Add to dashboard Cite

Understanding superconductivity requires detailed knowledge of the normal electronic state from which it emerges. A nematic electronic state that breaks the rotational symmetry of the lattice can potentially promote unique scattering relevant for superconductivity. Here, we investigate the normal transport of superconducting FeSe1−xSx across a nematic phase transition using high magnetic fields up to 69 T to establish the temperature and field-dependencies. We find that the nematic state is an anomalous non-Fermi liquid, dominated by a linear resistivity at low temperatures that can transform into a Fermi liquid, depending on the composition x and the impurity level. Near the nematic end point, we find an extended temperature regime with ∼ T 1.5 resistivity. The transverse magnetoresistance inside the nematic phase has as a ∼ H 1.55 dependence over a large magnetic field range and it displays an unusual peak at low temperatures inside the nematic phase. Our study reveals anomalous transport inside the nematic phase, driven by the subtle interplay between the changes in the electronic structure of a multi-band system and the unusual scattering processes affected by large magnetic fields and disorder.Magnetic field is a unique tuning parameter that can suppress superconductivity to reveal the normal low-temperature electronic behavior of many unconventional superconductors [1,2]. High-magnetic fields can also induce new phases of matter, probe Fermi surfaces and determine the quasi-particle masses from quantum oscillations in the proximity of quantum critical points [1,3]. In unconventional superconductors, close to antiferromagnetic critical regions, an unusual scaling between a linear resistivity in temperature and magnetic fields was found [4,5]. Magnetic fields can also induce metal-toinsulator transitions, as in hole-doped cuprates, where superconductivity emerges from an exotic electronic ground state [2].FeSe is a unique bulk superconductor with T c ∼ 9 K which displays a variety of complex and competing electronic phases [6]. FeSe is a bad metal at room temperature and it enters a nematic electronic state below T s ∼ 87 K. This nematic phase is characterized by multi-band shifts driven by orbital ordering that lead to Fermi surface distortions [6,7]. Furthermore, the electronic ground state is that of a strongly correlated system and the quasiparticle masses display orbital-dependent enhancements [7,8]. FeSe shows no long-range magnetic order at ambient pressure, but complex magnetic fluctuations are present at high energies over a large temperature range [9]. Below T s , the spin-lattice relaxation rate from NMR experiments is enhanced as it captures the low-energy tail of the stripe spin-fluctuations [10,11]. Furthermore, recent µSR studies invoke the close proximity of FeSe to a magnetic quantum critical point as the muon relaxation rate shows unusual temperature dependence inside the nematic state [12].The changes in the electronic structure and magnetic fluctuations of FeSe can have profound implicatio...

show abstract

Section: Resultsmentioning

confidence: 85%

“…As nematicity is suppressed, it creates ideal conditions to explore a potential nematic critical point [17] in the absence of magnetism. The superconducting dome extends outside the nematic state but anisotropic pairing remains robust [18] and a different superconducting state was suggested to be stabilized in the tetragonal phase [19].…”

mentioning

confidence: 99%

Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1−xSx

Bristow

Reiss

Haghighirad

et al. 2020

Phys. Rev. Research

View full text Add to dashboard Cite

show abstract

“…We then plot the 2D Fourier transform of L(r, ω), in moment space, and directly compare our results with the QPI data from Ref. [13].…”

Section: Methodsmentioning

confidence: 99%

“…Recently, a similar discrepancy has been encountered in the electronic structure of FeSe measured by Quasiparticle Interference (QPI) [12][13][14], where, again, theoretical calculations can not explain the data without assuming an additional form of anisotropy [14]. Ref.…”

mentioning

confidence: 85%

See 1 more Smart Citation

kz Selective Scattering within Quasiparticle Interference Measurements of FeSe

et al. 2019

View full text Add to dashboard Cite

Quasiparticle interference (QPI) provides a wealth of information relating to the electronic structure of a material. However, it is often assumed that this information is limited to two-dimensional electronic states. Here, we provide direct evidence that out-of-plane scattering vectors can also be observed within QPI experiments. We focus on the case of FeSe, where detailed photoemission and QPI data are available. By using a three-dimensional tight binding model, fit directly to photoemission measurements, we show that the highly anisotropic scattering vectors, measured by QPI, can be directly reproduced using a model of FeSe which includes both kz = 0 and kz = π states. This result unifies both tunnelling and photoemission based experiments on FeSe and highlights the importance of out-of-plane scattering vectors within the surface sensitive technique of QPI. arXiv:1906.02150v1 [cond-mat.supr-con]

show abstract

Orientational Order Parameters for Arbitrary Quantum Systems

Vrugt

Wittkowski

2020

Annalen der Physik

View full text Add to dashboard Cite

The concept of quantum-mechanical nematic order, which is important in systems such as superconductors, is based on an analogy to classical liquid crystals, where order parameters are obtained through orientational expansions. This method is generalized to quantum mechanics based on an expansion of Wigner functions. This provides a unified framework applicable to arbitrary quantum systems. The formalism recovers the standard definitions for spin systems. For Fermi liquids, the formalism reveals the nonequivalence of various definitions of the order parameter used in the literature. Moreover, new order parameters for quantum molecular systems with low symmetry are derived, which cannot be properly described with the usual nematic tensors.

show abstract

Two distinct superconducting pairing states divided by the nematic end point in FeSe _{1−
x} S _x

Abstract: Scanning tunneling microscopy reveals the relationship between nematicity and superconductivity in an iron-based superconductor.

Cited by 99 publications

References 51 publications

Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1−xSx

Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1−xSx

kz Selective Scattering within Quasiparticle Interference Measurements of FeSe

Orientational Order Parameters for Arbitrary Quantum Systems

Contact Info

Product

Resources

About

Two distinct superconducting pairing states divided by the nematic end point in FeSe 1− x S x

Abstract: Scanning tunneling microscopy reveals the relationship between nematicity and superconductivity in an iron-based superconductor.

Cited by 99 publications

References 51 publications

Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1−xSx

Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1−xSx

kz Selective Scattering within Quasiparticle Interference Measurements of FeSe

Orientational Order Parameters for Arbitrary Quantum Systems

Contact Info

Product

Resources

About

Two distinct superconducting pairing states divided by the nematic end point in FeSe _{1−
x} S _x