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Details Of 3d Electronic Structure Of Some Fe Based Superconductors And Their Superconducting Order Parameters
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Book Synopsis Details of 3D Electronic Structure of Some Fe-based Superconductors and Their Superconducting Order Parameters by : Yevhen S. Kushnirenko
Download or read book Details of 3D Electronic Structure of Some Fe-based Superconductors and Their Superconducting Order Parameters written by Yevhen S. Kushnirenko and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 High-Tc Superconductors Based on FeAs Compounds by : Yuri Izyumov
Download or read book High-Tc Superconductors Based on FeAs Compounds written by Yuri Izyumov and published by Springer Science & Business Media. This book was released on 2010-11-11 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physical properties and models of electronic structure are analyzed for a new class of high-TC superconductors which belong to iron-based layered compounds. Despite their variable chemical composition and differences in the crystal structure, these compounds possess similar physical characteristics, due to electron carriers in the FeAs layers and the interaction of these carriers with fluctuations of the magnetic order. A tremendous interest towards these materials is explained by the prospects of their practical use. In this monograph, a full picture of the formation of physical properties of these materials, in the context of existing theory models and electron structure studies, is given. The book is aimed at a broad circle of readers: physicists who study electronic properties of the FeAs compounds, chemists who synthesize them and specialists in the field of electronic structure calculations in solids. It is helpful not only to researchers active in the fields of superconductivity and magnetism, but also for graduate and postgraduate students and all those who would like to get acquaintained with this vivid area of the materials science.
Book Synopsis Transport and Thermodynamic Properties of Iron-based Superconductors by :
Download or read book Transport and Thermodynamic Properties of Iron-based Superconductors written by and published by . This book was released on 2014 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Iron-based superconductors (FeSCs) are a novel family of high-temperature superconductors. The rich phase diagrams exhibited by these compounds under various doping regimes, their multi-band electronic structure, the high superconducting critical temperature with exotic realization of order parameters, all contribute to this system being of considerable theoretical interest. In this Thesis, we report on our past work aimed at addressing possible signatures of the exotic superconducting (SC) order parameters (OPs), the coexistence with spin-density wave (SDW) phase, and fluctuations effects, as reflected in various transport or thermodynamic properties of these materials. We present a theoretical description of the differential conductance of point contacts between a normal metal and a multi-band superconductor with s+−-wave symmetry. We demonstrate that the interband impurity scattering broadens the coherent peak near the superconducting gap and significantly reduces its height even at relatively low scattering rates for an extended s+−-wave gap. Our mean-field treatment of the zero-temperature London penetration depth of a clean multi-band superconductor in the case when both SC and SDW orders coexist shows that the supefluid density closely follows the evolution of the superconducting order parameter as doping is increased, saturating to a BCS value in the pure superconducting state. Furthermore, a strong anisotropic in-pane penetration depth is shown to be induced by the SDW order. Beyond mean-field level, however, the monotonic behavior of both penetration depth, and specific heat jump is modified into a sharp peak near the tetracritical point - a point of intersection of four phase transition lines. We show that in the case of specific heat jump, this effect originates from thermal fluctuations of the SDW OP near the tetracritical point. Thermal fluctuations result in a power-law dependence of the specific heat jump fluctuation correction that is stronger than the contribution of mass renormalization due to quantum fluctuations of SDW in the vicinity of the putative critical point beneath the superconducting dome.
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 Superconductors by : Alexander Gabovich
Download or read book Superconductors written by Alexander Gabovich and published by BoD – Books on Demand. This book was released on 2015-08-24 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chapters included in the book describe recent developments in the field of superconductivity. The book deals with both the experiment and the theory. Superconducting and normal-state properties are studied by various methods. The authors presented investigations of traditional and new materials. In particular, studies of oxides, pnictides, chalcogenides and intermetallic compounds are included. The superconducting order parameter symmetry is discussed and consequences of its actual non-conventional symmetry are studied. Impurity and tunneling effects (both quasiparticle and Josephson ones) are among topics covered in the chapters. Special attention is paid to the competition between superconductivity and other instabilities, which lead to the Fermi surface gapping.
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 Springer Science & Business Media. This book was released on 2013-09-12 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis combines highly accurate optical spectroscopy data on the recently discovered iron-based high-temperature superconductors with an incisive theoretical analysis. Three outstanding results are reported: (1) The superconductivity-induced modification of the far-infrared conductivity of an iron arsenide with minimal chemical disorder is quantitatively described by means of a strong-coupling theory for spin fluctuation mediated Cooper pairing. The formalism developed in this thesis also describes prior spectroscopic data on more disordered compounds. (2) The same materials exhibit a sharp superconductivity-induced anomaly for photon energies around 2.5 eV, two orders of magnitude larger than the superconducting energy gap. The author provides a qualitative interpretation of this unprecedented observation, which is based on the multiband nature of the superconducting state. (3) The thesis also develops a comprehensive description of a superconducting, yet optically transparent iron chalcogenide compound. The author shows that this highly unusual behavior can be explained as a result of the nanoscopic coexistence of insulating and superconducting phases, and he uses a combination of two complementary experimental methods - scanning near-field optical microscopy and low-energy muon spin rotation - to directly image the phase coexistence and quantitatively determine the phase composition. These data have important implications for the interpretation of data from other experimental probes.
Book Synopsis Superconductivity in Fe-based Superconductors by :
Download or read book Superconductivity in Fe-based Superconductors written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Iron based superconductors(FeSC) are a new class of high temperature superconductors with very intriguing properties. These materials cannot be explained using the `conventional' logic of the `conventional' superconductors, and is also different from the Cuprates-the other popular class of high temperature superconductors. A complete description of the superconducting state in these materials requires a thorough understanding of its superconducting order parameter and the mechanism that leads to superconductivity-both of which are unsettled issues. In this thesis, we attempt to tackle some aspects of these issues. We first discuss, keeping the wisdom of Fermi-liquid theory in mind, the criteria for the superconducting instability in FeSC which is a lattice based system. Superconductivity in lattice based systems is different from well known BCS superconductivity. We make the point that the presence of electron and hole like carriers are crucial for the manifestations of such properties in the FeSCs. We then present a prescription to analyze the symmetries and structure of the superconducting order parameter (the gap) in generic lattice based systems where only the interaction amongst fermions close to the Fermi surface is important. We demonstrate the effectiveness of this prescription by applying it to the case of FeSCs where we study the evolution of the gap with injecting of carriers (of both hole and electron like). This prescription avoids use of heavy numerical studies and still gives results in excellent agreement with numerical and experimental studies. Elaborating more on the intriguing nature of FeSCs, we also point to the possibility of a new time reversal symmetry breaking s+is state that is unique to systems like these (due to presence of multiple Fermi pockets of the carriers) and discuss its experimental consequences.
Author :Karl-Heinz Bennemann Publisher :Springer Science & Business Media ISBN 13 :9783540442325 Total Pages :1166 pages Book Rating :4.4/5 (423 download)
Book Synopsis The Physics of Superconductors by : Karl-Heinz Bennemann
Download or read book The Physics of Superconductors written by Karl-Heinz Bennemann and published by Springer Science & Business Media. This book was released on 2004-04-07 with total page 1166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the second volume of a comprehensive two-volume treatise on superconductivity that represents the first such publication since the earlier widely acclaimed books by R. Parks. It systematically reviews the basic physics and recent advances in the field. Leading researchers describe the state of the art in conventional phonon-induced superconductivity, high-Tc superconductivity, and in novel superconductivity, including triplet pairing in the ruthenates. The second volume is largely concerned with novel superconductors, such as heavy-fermion metals and organic materials, and also includes granular superconductors. Important new results on current problems are presented in a manner designed to stimulate further research. Numerous illustrations, diagrams and tables make this book especially useful as a reference work for students, teachers and researchers. Volume 1 treats Conventional and High-Tc Superconductors (3-540-43883-1).
Book Synopsis Non-Universal Superconducting Gap Structure in Iron-Pnictides Revealed by Magnetic Penetration Depth Measurements by : Kenichiro Hashimoto
Download or read book Non-Universal Superconducting Gap Structure in Iron-Pnictides Revealed by Magnetic Penetration Depth Measurements written by Kenichiro Hashimoto and published by Springer. This book was released on 2016-05-01 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book shows that superconducting gap structure in iron-based superconductors depends on detailed electronic structure via magnetic penetration depth measurements, and that gap structure in iron-pnictides can be interpreted in the framework of A1g symmetry.
Book Synopsis Phase Transitions and Anomalous Compressibility in 1-2-2 Fe-based Superconductors by : Walter O. Uhoya
Download or read book Phase Transitions and Anomalous Compressibility in 1-2-2 Fe-based Superconductors written by Walter O. Uhoya and published by . This book was released on 2014 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interplay of pressure and chemistry play an important role in discovery of novel properties such as high temperature superconductivity (high-Tc). In 2008, Hosono et al discovered superconductivity at 26 K in iron-based layered LaFeAsO (1-x)Fx. This observation was a surprise since iron based compounds are generally known to be magnetic and non-superconducting. This was quickly followed by the discovery of high temperature superconductivity in a second class of Fe-based layered pnictides AFe2As2 (1-2-2) (A= Ba, Sr, Ca, Eu). The undoped (parent) 1-2-2 compounds are non-superconducting at ambient pressure but become superconducting when their structures are tuned by the application of high pressure or through chemical doping. Application of high pressures is advantageous over chemical doping in that it provides a clean method to tune the electronic properties that determine the superconducting and magnetic states of the novel materials. Interplay of pressure induced structural transitions, magnetic and superconducting properties of Fe-based materials is not well understood and this may form a foundation for testing present theories, discovering materials with higher-Tc for wide industrial applications close to room temperature, and may lead to better theories for solving the long standing problem of high-Tc superconductivity. In my work, I have used designer diamond anvil cell (DAC) to study the electrical transport properties of 1-2-2 parents of iron based superconductors under extreme conditions of pressure and low temperatures. I have used high pressure and low temperature time of flight neutron diffraction technique at the Spallation Neutron Source and synchrotron x-ray diffraction techniques at the Advance Photon Source to determine and refine the crystallographic parameters of the 1-2-2 materials under extreme conditions, and to relate their transport and structural properties under high pressures. My works have resulted into a discovery of anomalous compressibility and a concurrent tetragonal to collapsed tetragonal (T-cT) isostructural phase transition in 1-2-2 parents of iron-based superconductors. We showed that the anomaly is a common phenomenon for pure and doped ThCr2Si2 type pnictides of the type AT2As2 (A= divalent alkaline earth or rare earth element Ba, Ca, Sr, Eu; T=transition metal). We determine a general relation for predicting isostructural T-cT phase transition pressure for any 1-2-2 pnictide given its ambient pressure volume. Our work suggests that the collapsed tetragonal phase is non-superconducting. We have establish how onset of pressure induced superconductivity (TConset) in 1-2-2 parent materials depends on the compression behavior of As-Fe-As tetrahedral bond angles, tetragonal lattice parameter c, Fe2As2 layer thickness and As-As inter-atomic bond distance for parent 1-2-2 materials. The evolution of pressure driven tetragonal distortion, quantitative crystallographic parameters and pressure-volume equation of state for 1-2-2 materials under high pressures are presented up to 70 GPa and low temperatures down to 4 K.
Book Synopsis The Symmetry of the Electronic States and Order Parameter in the High Temperature Superconductor Bi2Sr2Ca1Cu2O8+x by : Ronald James Kelley
Download or read book The Symmetry of the Electronic States and Order Parameter in the High Temperature Superconductor Bi2Sr2Ca1Cu2O8+x written by Ronald James Kelley and published by . This book was released on 1994 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Angle-Resolved Photoemission Spectroscopy on Electronic Structure and Electron-Phonon Coupling in Cuprate Superconductors by :
Download or read book Angle-Resolved Photoemission Spectroscopy on Electronic Structure and Electron-Phonon Coupling in Cuprate Superconductors written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In addition to the record high superconducting transition temperature (T{sub c}), high temperature cuprate superconductors are characterized by their unusual superconducting properties below T{sub c}, and anomalous normal state properties above T{sub c}. In the superconducting state, although it has long been realized that superconductivity still involves Cooper pairs, as in the traditional BCS theory, the experimentally determined d-wave pairing is different from the usual s-wave pairing found in conventional superconductors. The identification of the pairing mechanism in cuprate superconductors remains an outstanding issue. The normal state properties, particularly in the underdoped region, have been found to be at odd with conventional metals which is usually described by Fermi liquid theory; instead, the normal state at optimal doping fits better with the marginal Fermi liquid phenomenology. Most notable is the observation of the pseudogap state in the underdoped region above T{sub c}. As in other strongly correlated electrons systems, these unusual properties stem from the interplay between electronic, magnetic, lattice and orbital degrees of freedom. Understanding the microscopic process involved in these materials and the interaction of electrons with other entities is essential to understand the mechanism of high temperature superconductivity. Since the discovery of high-T{sub c} superconductivity in cuprates, angle-resolved photoemission spectroscopy (ARPES) has provided key experimental insights in revealing the electronic structure of high temperature superconductors. These include, among others, the earliest identification of dispersion and a large Fermi surface, an anisotropic superconducting gap suggestive of a d-wave order parameter, and an observation of the pseudogap in underdoped samples. In the mean time, this technique itself has experienced a dramatic improvement in its energy and momentum resolutions, leading to a series of new discoveries not thought possible only a decade ago. This revolution of the ARPES technique and its scientific impact result from dramatic advances in four essential components: instrumental resolution and efficiency, sample manipulation, high quality samples and well-matched scientific issues. The purpose of this treatise is to go through the prominent results obtained from ARPES on cuprate superconductors. Because there have been a number of recent reviews on the electronic structures of high-T{sub c} materials, we will mainly present the latest results not covered previously, with a special attention given on the electron-phonon interaction in cuprate superconductors. What has emerged is rich information about the anomalous electron-phonon interaction well beyond the traditional views of the subject. It exhibits strong doping, momentum and phonon symmetry dependence, and shows complex interplay with the strong electron-electron interaction in these materials. ARPES experiments have been instrumental in identifying the electronic structure, observing and detailing the electron-phonon mode coupling behavior, and mapping the doping evolution of the high-T{sub c} cuprates. The spectra evolve from the strongly coupled, polaronic spectra seen in underdoped cuprates to the Migdal-Eliashberg like spectra seen in the optimally and overdoped cuprates. In addition to the marked doping dependence, the cuprates exhibit pronounced anisotropy with direction in the Brillouin zone: sharp quasiparticles along the nodal direction that broaden significantly in the anti-nodal region of the underdoped cuprates, an anisotropic electron-phonon coupling vertex for particular modes identified in the optimal and overdoped compounds, and preferential scattering across the two parallel pieces of Fermi surface in the antinodal region for all doping levels. This also contributes to the pseudogap effect. To the extent that the Migdal-Eliashberg picture applies, the spectra of the cuprates bear resemblance to that seen in established strongly coupled electron-phonon superconductors such as Pb. On the other hand, the cuprates deviate from this conventional picture. In the underdoped regime, the carriers are best understood as small polarons in an antiferromagnetic, highly electron correlated background, while the doped compounds require an anisotropic electron-phonon vertex to detail the prominent mode coupling signatures in the superconducting state. Electronic vertex corrections to the electron-phonon coupling furthermore may enhance, and for certain phonons, determine, the anisotropy of the electron-phonon coupling. A consistent picture emerges of the cuprates, combining strong, anisotropic electron-phonon coupling, particular phonon modes that could give rise to such a coupling, and an electron-electron interaction modifying the el-ph vertex.
Book Synopsis Magnetism and Superconductivity in Iron-based Superconductors as Probed by Nuclear Magnetic Resonance by : Franziska Hammerath
Download or read book Magnetism and Superconductivity in Iron-based Superconductors as Probed by Nuclear Magnetic Resonance written by Franziska Hammerath and published by Springer Science & Business Media. This book was released on 2012-08-31 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear Magnetic Resonance (NMR) has been a fundamental player in the studies of superconducting materials for many decades. This local probe technique allows for the study of the static electronic properties as well as of the low energy excitations of the electrons in the normal and the superconducting state. On that account it has also been widely applied to Fe-based superconductors from the very beginning of their discovery in February 2008. This dissertation comprises some of these very first NMR results, reflecting the unconventional nature of superconductivity and its strong link to magnetism in the investigated compounds LaO1–xFxFeAs and LiFeAs.
Book Synopsis On the Properties of Novel Superconductors by : Heshmatollah Yavari
Download or read book On the Properties of Novel Superconductors written by Heshmatollah Yavari and published by BoD – Books on Demand. This book was released on 2020-07-29 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the discovery of superconductivity, a great number of theoretical and experimental efforts have been made to describe this new phase of matter that emerged in many body systems. In this regard, theoretical models have been presented; the most famous of which was the BCS theory that can only describe conventional superconductors. With the discovery of new class superconductors, the superconducting mechanism became a new challenge in the field of condensed matter physics. This unexpected discovery opened a new area in the history of superconductivity, and experimental researchers started trying to find new compounds in this class of superconductors. These superconductors are often characterized by the anisotropic character in the superconducting gap function with nodes along a certain direction in the momentum space. Since the pairing interaction has an important role in the superconducting gap structure, its determination is very important to explain the basic pairing mechanism.In this regard, this book includes valuable theoretical and experimental discussions about the properties of superconductors. Here you will find valuable research describing the properties of unconventional superconductors.
Book Synopsis Electronic Structure Properties and High Pressure Experimentation of Superconducting Or Possibly Superconducting Systems by : Hahnbidt Rhee
Download or read book Electronic Structure Properties and High Pressure Experimentation of Superconducting Or Possibly Superconducting Systems written by Hahnbidt Rhee and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The following compounds were studied primarily for their superconducting properties or their potential to exhibit superconductivity. The layered ternary sp conductor NaAlSi, possessing the iron-pnictide "111" crystal structure, superconducts at 7 K. Using density functional methods, it is shown that this compound is an intrinsic (self-doped) low-carrier-density semimetal with a number of unusual features. Covalent Al-Si valence bands provide the holes, and free-electron-like Al 3s bands, which propagate in the channel between the neighboring Si layers, dip just below the Fermi level to create the electron carriers. The Fermi level lies in a narrow and sharp peak within a pseudogap in the density of states. The small peak arises from valence bands which are nearly of pure Si, quasi-two-dimensional, flat, and coupled to Al conduction bands. The possibility of a non-phononic pairing mechanism is discussed. The hexagonal Laves phase of CaLi2, nonsuperconducting at ambient pressure, is a strong candidate for superconductivity at higher pressures. Zero resistance has been observed in CaLi2 at pressures above 11 GPa and temperatures as high as 13 K. However, it hasn't been ruled out that superconducting elemental Li instead may be the source of the superconductivity. The crystallographic structure of CaLi2 has been studied via powder x-ray diffraction at high pressures and low temperatures in a diamond anvil cell, in an attempt to measure the structural phase diagram in the superconducting regime. PuPt2In-- does not superconduct down to 2 K, despite its electronic and structural similarities with superconductor PuCoGa5 and other Pu-based superconductors. Results of generalized gradient approximation (GGA)+U calculations on PuPt2In-- and on hypothetical PuPt2Ga-- are discussed. The strength of the c-f hybridization of PuPt2In-- is similar to that of PuCoIn5, while PuPt2Ga-- is less localized and more like PuCoGa5. The bare and f-weighted susceptibility within the constant matrix element approximation is calculated, showing a maximum at q[subscript x] = q[subscript y] = 0.5. A similar and slightly stronger maximum is also found in PuCoGa5 and PuCoIn5. The absence of superconductivity in PuPt2In-- is examined based on the results of the calculations.
