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Elastoresistance Of Iron Based Superconductors
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Book Synopsis Elastoresistance of Iron-based Superconductors by : Johanna Palmstrom
Download or read book Elastoresistance of Iron-based Superconductors written by Johanna Palmstrom and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Strong electronic nematic fluctuations have been discovered near optimal doping for several families of Fe-based superconductors, raising the question of what role, if any, these fluctuations might play in the superconducting pairing interaction. Underdoped Fe-based superconductors undergo a second order tetragonal-to-orthorhombic structural transition driven by electronic nematic order that accompanies or precedes an antiferromagnetic transition and borders the superconducting dome. In the tetragonal phase Fe-based superconductors are highly sensitive to perturbations of the same symmetry as the nematic order, such as antisymmetric (in this case B2g) strain. Elastoresistivity is described by a high rank tensor (fourth-rank +) as it relates changes in resistivity (second-rank) to strain (second-rank) experienced by a material and is a sensitive probe of broken symmetries. Previously, elastoresistivity measurements of the linear resistivity response to antisymmetric strain have revealed a divergent electronic nematic susceptibility in underdoped materials and has been used to characterize the nematic fluctuations in the tetragonal phase above the zero-field superconducting dome. In this work, I develop two new extensions to elastoresistivity measurements in order to probe the effects of electronic nematic fluctuations in greater detail in a representative family of these materials, the prototypical electron-doped pnictide Ba(Fe(1-x)Cox)2As2. First, I go beyond the first order response via a measurement of the nonlinear elastoresistivity. I find that the strong nematic fluctuations play a large role in the isotropic electronic response of these materials--as evidenced by a diverging nonlinear symmetric elastoresistivity response to antisymmetric strain. Second, I performed elastoresistivity measurements in magnetic fields large enough to suppress superconductivity to investigate the potential that the nematic fluctuations are related to a quantum critical point. I do not observe a magnetic field dependence of the nematic fluctuations and find that they continue to grow with decreasing temperature beneath the zero-field superconducting dome. I performed high magnetic field measurements on samples with a fine distribution of dopings and find that close to the putative quantum critical point, the nematic susceptibility appears to obey power law behavior over almost a decade of variation in composition. This is consistent with basic notions of nematic quantum criticality which, for clean systems, is associated with power law scaling in both doping and temperature. Paradoxically, however, I also find that the temperature dependence of the nematic susceptibility for compositions close to the critical value cannot be described by a single power law.
Book Synopsis Iron-based Superconductors by : Nan Lin Wang
Download or read book Iron-based Superconductors written by Nan Lin Wang and published by CRC Press. This book was released on 2012-11-19 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: From fundamental physics point of view, iron-based superconductors have properties that are more amenable to band structural calculations. This book reviews the progress made in this fascinating field. With contributions from leading experts, the book provides a guide to understanding materials, physical properties, and superconductivity mechanism
Book Synopsis Nematicity in iron-based superconductors by : Qisi Wang
Download or read book Nematicity in iron-based superconductors written by Qisi Wang and published by Frontiers Media SA. This book was released on 2023-02-15 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Iron Pnictide Superconductors by : Ferdinando Mancini
Download or read book The Iron Pnictide Superconductors written by Ferdinando Mancini and published by Springer. This book was released on 2017-05-25 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers different aspects of the physics of iron-based superconductors ranging from the theoretical, the numerical and computational to the experimental ones. It starts from the basic theory modeling many-body physics in Fe-superconductors and other multi-orbital materials and reaches up to the magnetic and Cooper pair fluctuations and nematic order. Finally, it offers a comprehensive overview of the most recent advancements in the experimental investigations of iron based superconductors.
Book Synopsis Iron-Based Superconductivity by : Peter D. Johnson
Download or read book Iron-Based Superconductivity written by Peter D. Johnson and published by Springer. This book was released on 2015-01-06 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents an in-depth review of experimental and theoretical studies on the newly discovered Fe-based superconductors. Following the Introduction, which places iron-based superconductors in the context of other unconventional superconductors, the book is divided into three sections covering sample growth, experimental characterization, and theoretical understanding. To understand the complex structure-property relationships of these materials, results from a wide range of experimental techniques and theoretical approaches are described that probe the electronic and magnetic properties and offer insight into either itinerant or localized electronic states. The extensive reference lists provide a bridge to further reading. Iron-Based Superconductivity is essential reading for advanced undergraduate and graduate students as well as researchers active in the fields of condensed matter physics and materials science in general, particularly those with an interest in correlated metals, frustrated spin systems, superconductivity, and competing orders.
Book Synopsis Electronic Nematicity in Iron-based Superconductors by : Hsueh-Hui Kuo
Download or read book Electronic Nematicity in Iron-based Superconductors written by Hsueh-Hui Kuo and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Emerging evidence for the presence of strongly anisotropic electronic states in the underdoped regime of both cuprate and iron-based high temperature superconductors suggests the possibility of an important role for electronic nematic order in these materials. The central theme of my thesis work has been the experimental study of electronic nematicity in iron-based superconductors via measurement of resistivity anisotropy. To do this, I have developed several new experimental techniques, on the one hand enabling detwinning of sub-mm size single crystals in the broken-symmetry orthorhombic state, and on the other hand revealing the nematic susceptibility in the high-symmetry tetragonal state. A major part of my thesis work has involved measurement of the elastoresistance; that is, the change in the resistance of a material as a consequence of the strains that it experiences. In this thesis, I will show how differential elastoresistance measurements can directly reveal the nematic susceptibility of a material in the tetragonal state. I will introduce the appropriate tensor formalism necessary to describe these measurements, and describe an experimental technique to determine these coefficients using piezoelectric stacks to provide anisotropic bi-axial strain. Results in the tetragonal state of various underdoped families based on the parent compound BaFe2As2 explicitly demonstrate that the tetragonal-to-orthorhombic structural transition in these materials is fundamentally driven by an electronic nematic instability. These results also suggest that the resistivity anisotropy in the paramagnetic orthorhombic state is dominated by the Fermi surface anisotropy, rather than an anisotropy in the scattering rate. Finally, similar measurements of a wide variety of optimally doped iron-pnictides and iron-chalcogenides reveal that a divergence of the nematic susceptibility in the B2g symmetry channel appears to be a generic feature of optimally-doped iron-based superconductors. In addition to the above, I also employ a mechanical detwinning technique to reveal the resistivity anisotropy in the orthorhombic state of the same Fe-based superconductors. For the isovalently-substituted material BaFe2(As1-xPx)2, these measurements reveal a strong coupling between external stress and both the Neel temperature and the superconducting critical temperature.
Book Synopsis Elastic and Inelastic Scanning Tunneling Spectroscopy on Iron-Based Superconductors by : Jasmin Maria Jandke
Download or read book Elastic and Inelastic Scanning Tunneling Spectroscopy on Iron-Based Superconductors written by Jasmin Maria Jandke and published by Saint Philip Street Press. This book was released on 2020-10-09 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Within this work, the pairing mechanism of conventional (Pb) and unconventional superconductors (SrFe2(As1-xPx )2, FeSe, FeSe/STO) was investigated experimentally by means of elastic and inelastic tunneling spectroscopy at temperatures down to 30 mK. The distinction between elastic and inelastic contributions to tunneling data was elaborated. The results help to identify conventional (phonon-mediated) and unconventional (e.g. spin-?uctuation mediated) superconductivity. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.
Book Synopsis Iron Based Superconductors by : Shahbazi Mahboobeh
Download or read book Iron Based Superconductors written by Shahbazi Mahboobeh and published by LAP Lambert Academic Publishing. This book was released on 2015-05-28 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discovered in 2008, iron based superconductors are the latest high temperature superconductors which have aroused enormous attention in the scientific community. Finding superconductivity in compounds containing iron, after two decades of intensive research on the high temperature cuprates was a surprise to the scientists in this field, as they thought that the magnetic nature of iron would disrupt the pairing of electrons in the superconducting state. These materials exhibit high upper critical field, high critical current density, very high intrinsic pinning potential and low anisotropy compared with MgB2 and other conventional superconductors, and even cuprate superconductors. Iron based superconductors would be good candidates for use in electricity generators, cheaper medical imaging scanners, and extremely fast levitating trains.
Book Synopsis Charge Dynamics in 122 Iron-Based Superconductors by : Aliaksei Charnukha
Download or read book Charge Dynamics in 122 Iron-Based Superconductors written by Aliaksei Charnukha and published by . This book was released on 2013-09-30 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Magnetic Excitations in Iron-based Superconductors by : Florian Tim Waßer
Download or read book Magnetic Excitations in Iron-based Superconductors written by Florian Tim Waßer and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Focus on the Electromagnetic Properties of Iron-based Superconductors by : Ruslan Prozorov
Download or read book Focus on the Electromagnetic Properties of Iron-based Superconductors written by Ruslan Prozorov and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nematic Fluctuations, Fermiology and the Pairing Potential in Iron-Based Superconductors by : Florian Kretzschmar
Download or read book Nematic Fluctuations, Fermiology and the Pairing Potential in Iron-Based Superconductors written by Florian Kretzschmar and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Magnetism in the Iron-based Superconductors by : Keith M. Taddei
Download or read book Magnetism in the Iron-based Superconductors written by Keith M. Taddei and published by . This book was released on 2016 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: With nearly innumerable applications, superconductivity stands as a holy grail in the research of quantum phenomena. Understanding the mechanism that begets the fabled pairing of electrons which leads to zero resistance is the most significant undertaking in order to bring to fruition all of superconductivity's splendor. Yet the interaction which couples electrons in the most promising family of superconductors known as unconventional superconductors, which show the highest Tc's and largest upper critical fields remains a mystery. Intense study over the past several decades on the cuprate superconductors has allowed for the identification of several candidate mechanisms --- cardinal of which is magnetic fluctuations --- however as of yet the question still remains. Recently, the discovery of the iron-based superconductors has provided another fruitful avenue through which this mechanism can be probed. Excitingly in these materials superconductivity not only arises near a magnetic instability - a situation which is expected to be particularly suited for engendering superconductivity should magnetic fluctuations be the pairing mechanism - but also exhibit the microscopic co-existence of the two presumably adversarial phenomena. In the work presented here the powerful techniques of neutron and x-ray diffraction will be used to study two particularly interesting members of this family: the intercalated iron-selenide CsxFe 2--xSe2 and two members of the iron-arsenide 122 family (BaFe2(As1--xPx)2 and Sr1--xNaxFe2As 2). Though isostructural at high temperatures, these two materials behave remarkably differently and the idiosyncratic manifestations of superconductivity and ordered magnetism in either give clues as to how the latter might stabilize the former. The iron-selenides will be shown to exhibit a complex phase space with phase separation leading to stabilization of magnetism and superconductivity in separate phases. The structure, behavior and complex vacancy ordering of this phase-separated state will be elucidated and the superconductivity attributed to a pseudo-stable minority phase. Detailed phase diagrams will be constructed for the related BaFe2(As1--xPx) 2 and Sr1--xNaxFe2 As2 compounds leading to a direct comparison of the effects driving of either doping regime. A strong magneto-elastic coupling will be established in both of these materials and a new magnetic phase will be mapped in Sr1--xNaxFe2As2. These observations will lead to a discussion of the role of magnetic fluctuations in the overall behavior of the material. The results of inelastic and elastic diffraction experiments will be combined with the results of the local probe M?ssbauer spectroscopy technique in order to determine magnetic fluctuations as the primary order parameter in the phase evolution of the iron-based superconductors, and therefore their importance in establishment of superconductivity as the ground state of these materials.
Book Synopsis The Magnetostructural Transition in Iron-based Superconductors and Their Parent Compounds by : Miles K. Frampton
Download or read book The Magnetostructural Transition in Iron-based Superconductors and Their Parent Compounds written by Miles K. Frampton and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, I study the behavior of the magnetostructural transition of several iron-based superconductors and their parent compounds under applied magnetic field and uniaxial pressure. Specifically, I studied the resistance of CaFe2As2 under ab-plane uniaxial pressure and the magnetoresistance of Fe1.13Te, BaFe2As2, and SrFe2As2. In addition, a technique borrowed from the magnetism community called First Order Reversal Curve Analysis was successfully applied to Fe1.03Te under applied magnetic field and uniaxial pressure, Fe1.13Te under applied magnetic field, and CaFe2As2 under applied magnetic field. This novel application of this technique could have extensive application in the study of superconductors and other materials that display hysteresis. Furthermore, pulsed magnetic fieldmagnetoresistance data of Fe1.13Te is presented.
Download or read book Special Section written by and published by . This book was released on 2010 with total page 3813 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Theory of Spin-fluctuation Induced Superconductivity in Iron-based Superconductors by : Junhua Zhang
Download or read book Theory of Spin-fluctuation Induced Superconductivity in Iron-based Superconductors written by Junhua Zhang and published by . This book was released on 2011 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Theory of Spin-fluctuation Induced Superconductivity in Iron-based Superconductors by :
Download or read book Theory of Spin-fluctuation Induced Superconductivity in Iron-based Superconductors written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation we focus on the investigation of the pairing mechanism in the recently discovered high-temperature superconductor, iron pnictides. Due to the proximity to magnetic instability of the system, we considered short-range spin fluctuations as the major mediating source to induce superconductivity. Our calculation supports the magnetic fluctuations as a strong candidate that drives Cooper-pair formation in this material. We find the corresponding order parameter to be of the so-called ss-wave type and show its evolution with temperature as well as the capability of supporting high transition temperature up to several tens of Kelvin. On the other hand, our itinerant model calculation shows pronounced spin correlation at the observed antiferromagnetic ordering wave vector, indicating the underlying electronic structure in favor of antiferromagnetic state. Therefore, the electronic degrees of freedom could participate both in the magnetic and in the superconducting properties. Our work shows that the interplay between magnetism and superconductivity plays an important role to the understanding of the rich physics in this material. The magnetic-excitation spectrum carries important information on the nature of magnetism and the characteristics of superconductivity. We analyze the spin excitation spectrum in the normal and superconducting states of iron pnictides in the magnetic scenario. As a consequence of the sign-reversed gap structure obtained in the above, a spin resonance mode appears below the superconducting transition temperature. The calculated resonance energy, scaled with the gap magnitude and the magnetic correlation length, agrees well with the inelastic neutron scattering (INS) measurements. More interestingly, we find a common feature of those short-range spin fluctuations that are capable of inducing a fully gapped ss state is the momentum anisotropy with elongated span along the direction transverse to the antiferromagnetic momentum transfer. This calculated intrinsic anisotropy exists both in the normal and in the superconducting state, which naturally explains the elliptically shaped magnetic responses observed in INS experiments. Our detailed calculation further shows that the magnetic resonance mode exhibits an upward dispersion-relation pattern but anisotropic along the transverse and longitudinal directions. We also perform a qualitative analysis on the relationship between the anisotropic momentum structure of the magnetic fluctuations and the stability of superconducting phase by intraorbital but interband pair scattering to show the consistency of the magnetic mechanism for superconductivity. As discussed for cuprates, an important identification of the mediating boson is from the fermionic spectrum. We study the spectral function in the normal and superconducting state. Not only do we extract the gap magnitude on the electron- and hole-pockets to show the momentum structure of the gap, but also find a peak-dip-hump feature in the electron spectrum, which reflects the feedback from the spin excitations on fermions. This serves as an interpretation of the kink structure observed in ARPES measurements.
