scholarly journals Emerging symmetric strain response and weakening nematic fluctuations in strongly hole-doped iron-based superconductors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
P. Wiecki ◽  
M. Frachet ◽  
A.-A. Haghighirad ◽  
T. Wolf ◽  
C. Meingast ◽  
...  
Keyword(s):  
Hole Doping ◽  
Strain Response ◽  
Iron Based Superconductors ◽  
Optimal Doping ◽  
Plane Symmetric ◽  
Nematic Order ◽  
Unconventional Superconductors ◽  
Iron Based ◽  
Electronic Nematicity ◽  
Ordered State

AbstractElectronic nematicity is often found in unconventional superconductors, suggesting its relevance for electronic pairing. In the strongly hole-doped iron-based superconductors, the symmetry channel and strength of the nematic fluctuations, as well as the possible presence of long-range nematic order, remain controversial. Here, we address these questions using transport measurements under elastic strain. By decomposing the strain response into the appropriate symmetry channels, we demonstrate the emergence of a giant in-plane symmetric contribution, associated with the growth of both strong electronic correlations and the sensitivity of these correlations to strain. We find weakened remnants of the nematic fluctuations that are present at optimal doping, but no change in the symmetry channel of nematic fluctuations with hole doping. Furthermore, we find no indication of a nematic-ordered state in the AFe2As2 (A = K, Rb, Cs) superconductors. These results revise the current understanding of nematicity in hole-doped iron-based superconductors.

scholarly journals Momentum Dependence of the Nematic Order Parameter in Iron-Based Superconductors

2019 ◽  
Vol 123 (6) ◽  
Author(s):  
H. Pfau ◽  
S. D. Chen ◽  
M. Yi ◽  
M. Hashimoto ◽  
C. R. Rotundu ◽  
...  
Keyword(s):  
Order Parameter ◽  
Momentum Dependence ◽  
Iron Based Superconductors ◽  
Nematic Order ◽  
Iron Based

scholarly journals Orbital fluctuation theory in iron-based superconductors: -wave superconductivity, structure transition, and impurity-induced nematic order

2012 ◽  
Vol 152 (8) ◽  
pp. 718-727 ◽  
Author(s):  
Hiroshi Kontani ◽  
Yoshio Inoue ◽  
Tetsuro Saito ◽  
Youichi Yamakawa ◽  
Seiichiro Onari
Keyword(s):  
Fluctuation Theory ◽  
Iron Based Superconductors ◽  
Structure Transition ◽  
Nematic Order ◽  
Iron Based

scholarly journals What drives nematic order in iron-based superconductors?

2014 ◽  
Vol 10 (2) ◽  
pp. 97-104 ◽  
Author(s):  
R. M. Fernandes ◽  
A. V. Chubukov ◽  
J. Schmalian
Keyword(s):  
Iron Based Superconductors ◽  
Nematic Order ◽  
Iron Based

ANOMALOUS ELASTIC BEHAVIOR AND ITS CORRELATION WITH SUPERCONDUCTIVITY IN IRON-BASED SUPERCONDUCTOR Ba(Fe1-xCox)2As2

2012 ◽  
Vol 26 (19) ◽  
pp. 1230011 ◽  
Author(s):  
MASAHITO YOSHIZAWA ◽  
SHALAMUJIANG SIMAYI
Keyword(s):  
Elastic Behavior ◽  
Clear Correlation ◽  
Superconducting Transition ◽  
Strong Electron ◽  
Iron Based Superconductors ◽  
Unconventional Superconductors ◽  
Structural Fluctuation ◽  
Iron Based ◽  
Lattice Coupling ◽  
Quantum Critical Behavior

Elastic properties of iron-based superconductor Ba ( Fe 1-x Co x)2 As 2 with various Co concentrations x were reviewed. Among all elastic constants, C66 shows remarkable softening associated with the structural transition from tetragonal to orthorhombic. The amount of anomaly in C66 is 90% for the underdoped samples of x < 0.07 For the overdoped samples, the anomalies in C66 gradually disappear with the increasing of Co concentration. The elastic compliance S66 (= 1/C66) shows a quantum critical behavior, which behaves just like the magnetic susceptibility of unconventional superconductors. There exists a clear correlation between the superconducting transition temperature and the amount of anomaly in S66. It was suggested that the structural fluctuation, which is measured by S66, plays an important role in the emergence of superconductivity. The elastic anomaly of Ba ( Fe 1-x Co x)2 As 2 is characterized by a strong electron–lattice coupling, which would be originated from the 3d orbitals of iron. This might be a universal phenomenon not only in iron-based superconductors but also d-electron based superconductors. The results on Ba ( Fe 1-x Co x)2 As 2 would reveal relevant roles of the structural fluctuations due to the orbitals, which should be taken into account for the understanding of a whole picture of the superconductivity in iron-based superconductors and related materials.

scholarly journals Observation of an electronic order along [110] direction in FeSe

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kunliang Bu ◽  
Wenhao Zhang ◽  
Ying Fei ◽  
Yuan Zheng ◽  
Fangzhou Ai ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Correlation Length ◽  
Charge Order ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Nematic Order ◽  
Unconventional Superconductors ◽  
Iron Based ◽  
Electronic Order

AbstractMultiple ordered states have been observed in unconventional superconductors. Here, we apply scanning tunneling microscopy to probe the intrinsic ordered states in FeSe, the structurally simplest iron-based superconductor. Besides the well-known nematic order along [100] direction, we observe a checkerboard charge order in the iron lattice, which we name a [110] electronic order in FeSe. The [110] electronic order is robust at 77 K, accompanied with the rather weak [100] nematic order. At 4.5 K, The [100] nematic order is enhanced, while the [110] electronic order forms domains with reduced correlation length. In addition, the collective [110] order is gaped around [−40, 40] meV at 4.5 K. The observation of this exotic electronic order may shed new light on the origin of the ordered states in FeSe.

scholarly journals Novel electronic nematicity in heavily hole-doped iron pnictide superconductors

2020 ◽  
Vol 117 (12) ◽  
pp. 6424-6429 ◽  
Author(s):  
Kousuke Ishida ◽  
Masaya Tsujii ◽  
Suguru Hosoi ◽  
Yuta Mizukami ◽  
Shigeyuki Ishida ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Rotational Symmetry ◽  
Quantum Liquid ◽  
Iron Based Superconductors ◽  
Iron Pnictide ◽  
Tetragonal Lattice ◽  
Nematic State ◽  
Nematic Director ◽  
Iron Based ◽  
Electronic Nematicity

Electronic nematicity, a correlated state that spontaneously breaks rotational symmetry, is observed in several layered quantum materials. In contrast to their liquid-crystal counterparts, the nematic director cannot usually point in an arbitrary direction (XY nematics), but is locked by the crystal to discrete directions (Ising nematics), resulting in strongly anisotropic fluctuations above the transition. Here, we report on the observation of nearly isotropic XY-nematic fluctuations, via elastoresistance measurements, in hole-doped Ba1−xRbxFe2As2iron-based superconductors. While forx=0, the nematic director points along the in-plane diagonals of the tetragonal lattice, forx=1, it points along the horizontal and vertical axes. Remarkably, for intermediate doping, the susceptibilities of these two symmetry-irreducible nematic channels display comparable Curie–Weiss behavior, thus revealing a nearly XY-nematic state. This opens a route to assess this elusive electronic quantum liquid-crystalline state.

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