Superstripes Physics, 2nd Edition

A special issue of Condensed Matter (ISSN 2410-3896).

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 15675

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Rome International Center for Materials Science Superstripes (RICMASS), Via dei Sabelli 119A, 00185 Roma, Italy
Interests: synchrotron radiation research; protein fluctuations; active sites of metalloproteins; origin of life; selected molecules in prebiotic world; quantum phenomena in complex matter; quantum confinement; superstripes in complex matter; lattice complexity in transition metal oxides; high Tc superconductors; valence fluctuation materials
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Department of Physics, Columbia University, New York, NY 10027, USA
Interests: atomic, molecular, and optical physics; condensed matter physics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue will publish selected papers from the Superstripes 2023 meeting due to take place June 26–July 1, 2023 in Ischia, Italy.

The Superstripes 2023 meeting continues the successful series of international meetings. The first Stripes Conference was held in Rome in 1996 following an increased interest in the scientific international community’s emergence of new phenomena related to complexity in quantum matter. The aim of the 2023 Superstripes conference is to foster top-level scientific cultural advances, uniting selected world leaders in the field of new advances in quantum complex matter science. You are invited to contribute an article/review paper for possible publication in our Special Issue. Submissions will be rapidly reviewed and published shortly, if accepted.

Prof. Dr. Antonio Bianconi
Prof. Dr. Yasutomo Uemura
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Condensed Matter is an international peer-reviewed open access quarterly journal published by MDPI.

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Published Papers (12 papers)

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Research

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13 pages, 674 KiB  
Article
The Shrinking Fermi Liquid Scenario for Strange-Metal Behavior from Overdamped Optical Phonons
by Giovanni Mirarchi, Marco Grilli, Götz Seibold and Sergio Caprara
Condens. Matter 2024, 9(1), 14; https://doi.org/10.3390/condmat9010014 - 6 Feb 2024
Viewed by 1083
Abstract
We discuss how the interaction of electrons with an overdamped optical phonon can give rise to a strange-metal behavior over extended temperature and frequency ranges. Although the mode has a finite frequency, an increasing damping shifts spectral weight to progressively lower energies so [...] Read more.
We discuss how the interaction of electrons with an overdamped optical phonon can give rise to a strange-metal behavior over extended temperature and frequency ranges. Although the mode has a finite frequency, an increasing damping shifts spectral weight to progressively lower energies so that despite the ultimate Fermi liquid character of the system at the lowest temperatures and frequencies, the transport and optical properties of the electron system mimic a marginal Fermi liquid behavior. Within this shrinking Fermi liquid scenario, we extensively investigate the electron self-energy in all frequency and temperature ranges, emphasizing similarities and differences with respect to the marginal Fermi liquid scenario. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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11 pages, 543 KiB  
Article
A Theoretical Study of Doping Evolution of Phonons in High-Temperature Cuprate Superconductors
by Saheli Sarkar
Condens. Matter 2024, 9(1), 13; https://doi.org/10.3390/condmat9010013 - 6 Feb 2024
Cited by 1 | Viewed by 1315
Abstract
Hole-doped high-temperature copper oxide-based superconductors (cuprates) exhibit complex phase diagrams where electronic orders like a charge density wave (CDW) and superconductivity (SC) appear at low temperatures. The origins of these electronic orders are still open questions due to their complex interplay and correlated [...] Read more.
Hole-doped high-temperature copper oxide-based superconductors (cuprates) exhibit complex phase diagrams where electronic orders like a charge density wave (CDW) and superconductivity (SC) appear at low temperatures. The origins of these electronic orders are still open questions due to their complex interplay and correlated nature. These electronic orders can modify the phonons in the system, which has also been experimentally found in several cuprates as a softening in the phonon frequency at the CDW vector. Recent experiments have revealed that the softening in phonons in cuprates due to CDW shows intriguing behavior with increasing hole doping. Hole doping can also change the underlying Fermi surface. Therefore, it is an interesting question whether the doping-induced change in the Fermi surface can affect the softening of phonons, which in turn can reveal the nature of the electronic orders present in the system. In this work, we investigate this question by studying the softening of phonons in the presence of CDW and SC within a perturbative approach developed in an earlier work. We compare the results obtained within the working model to some experiments. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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11 pages, 1687 KiB  
Article
Dynamic Correlations in Disordered Systems: Implications for High-Temperature Superconductivity
by Takeshi Egami
Condens. Matter 2024, 9(1), 12; https://doi.org/10.3390/condmat9010012 - 3 Feb 2024
Viewed by 1237
Abstract
Liquids and gases are distinct in their extent of dynamic atomic correlations; in gases, atoms are almost uncorrelated, whereas they are strongly correlated in liquids. This distinction applies also to electronic systems. Fermi liquids are actually gas-like, whereas strongly correlated electrons are liquid-like. [...] Read more.
Liquids and gases are distinct in their extent of dynamic atomic correlations; in gases, atoms are almost uncorrelated, whereas they are strongly correlated in liquids. This distinction applies also to electronic systems. Fermi liquids are actually gas-like, whereas strongly correlated electrons are liquid-like. Doped Mott insulators share characteristics with supercooled liquids. Such distinctions have important implications for superconductivity. We discuss the nature of dynamic atomic correlations in liquids and a possible effect of strong electron correlations and Bose–Einstein condensation on the high-temperature superconductivity of the cuprates. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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9 pages, 874 KiB  
Article
Single-Band versus Two-Band Description of Magnetism in Infinite-Layer Nickelates
by Tharathep Plienbumrung, Maria Daghofer, Jean-Baptiste Morée and Andrzej M. Oleś
Condens. Matter 2023, 8(4), 107; https://doi.org/10.3390/condmat8040107 - 6 Dec 2023
Viewed by 1288
Abstract
We present a weak-coupling analysis of magnetism in infinite-layer nickelates, where we compare a single-band description with a two-band model. Both models predict that (i) hybridization due to hopping is negligible, and (ii) the magnetic properties are characterized [...] Read more.
We present a weak-coupling analysis of magnetism in infinite-layer nickelates, where we compare a single-band description with a two-band model. Both models predict that (i) hybridization due to hopping is negligible, and (ii) the magnetic properties are characterized by very similar dynamic structure factors, S(k,ω), at the points (π,π,0) and (π,π,π). This gives effectively a two-dimensional description of the magnetic properties. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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15 pages, 1416 KiB  
Article
Two-Dimensional Discommensurations: An Extension to McMillan’s Ginzburg–Landau Theory
by Lotte Mertens, Jeroen van den Brink and Jasper van Wezel
Condens. Matter 2023, 8(4), 100; https://doi.org/10.3390/condmat8040100 - 17 Nov 2023
Viewed by 1394
Abstract
Charge density waves (CDWs) profoundly affect the electronic properties of materials and have an intricate interplay with other collective states, like superconductivity and magnetism. The well-known macroscopic Ginzburg–Landau theory stands out as a theoretical method for describing CDW phenomenology without requiring a microscopic [...] Read more.
Charge density waves (CDWs) profoundly affect the electronic properties of materials and have an intricate interplay with other collective states, like superconductivity and magnetism. The well-known macroscopic Ginzburg–Landau theory stands out as a theoretical method for describing CDW phenomenology without requiring a microscopic description. In particular, it has been instrumental in understanding the emergence of domain structures in several CDW compounds, as well as the influence of critical fluctuations and the evolution towards or across lock-in transitions. In this context, McMillan’s foundational work introduced discommensurations as the objects mediating the transition from commensurate to incommensurate CDWs, through an intermediate nearly commensurate phase characterised by an ordered array of phase slips. Here, we extended the simplified, effectively one-dimensional, setting of the original model to a fully two-dimensional analysis. We found exact and numerical solutions for several types of discommensuration patterns and provide a framework for consistently describing multi-component CDWs embedded in quasi-two-dimensional atomic lattices. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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14 pages, 396 KiB  
Article
On the Evaluation of Higher-Harmonic-Current Responses for High-Field Spectroscopies in Disordered Superconductors
by Götz Seibold
Condens. Matter 2023, 8(4), 95; https://doi.org/10.3390/condmat8040095 - 13 Nov 2023
Viewed by 1154
Abstract
We discuss a formalism that allows for the calculation of a higher-harmonic-current response to a strong applied electric field for disordered superconducting systems described on the basis of tight-binding models with on- and/or intersite interactions. The theory is based on an expansion of [...] Read more.
We discuss a formalism that allows for the calculation of a higher-harmonic-current response to a strong applied electric field for disordered superconducting systems described on the basis of tight-binding models with on- and/or intersite interactions. The theory is based on an expansion of the density matrix in powers of the field amplitudes, where we solve the equation of motion for the individual components. This allows the evaluation of higher-order response functions on significantly larger lattices than one can achieve with a previously used approach, which is based on a direct temporal integration of the equation of motion for the complete density matrix. In the case of small lattices, where both methods can be applied by including also the contribution of collective modes, we demonstrate the agreement of the corresponding results. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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8 pages, 2820 KiB  
Article
Suppression of Stacking Order with Doping in 1T-TaS2−xSex
by Sharon S. Philip, Despina Louca, Matthew B. Stone and Alexander I. Kolesnikov
Condens. Matter 2023, 8(4), 89; https://doi.org/10.3390/condmat8040089 - 10 Oct 2023
Cited by 1 | Viewed by 1397
Abstract
In 1T-TaS2xSex, the charge density wave (CDW) state features a star of David lattice that expands across layers as the system becomes commensurate upon cooling. The layers can also order along the c-axis, and different stacking orders [...] Read more.
In 1T-TaS2xSex, the charge density wave (CDW) state features a star of David lattice that expands across layers as the system becomes commensurate upon cooling. The layers can also order along the c-axis, and different stacking orders have been proposed. Using neutron scattering on powder samples, we compared the stacking order previously observed in 1T-TaS2 when the system is doped with Se. While at low temperature, a 13c layer sequence stacking was observed in TaS2; this type of ordering was not evident with doping. Doping with Se results in a metallic state in which the Mott transition is suppressed, which may be linked to the absence of layer stacking. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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7 pages, 506 KiB  
Article
Ultrafast Pump–Probe Spectroscopy in Organic Dirac Electron Candidate α-(BETS)2I3
by Satoshi Tsuchiya, Masato Katsumi, Ryuhei Oka, Toshio Naito and Yasunori Toda
Condens. Matter 2023, 8(4), 88; https://doi.org/10.3390/condmat8040088 - 10 Oct 2023
Viewed by 1116
Abstract
Photo-induced carrier dynamics were measured in the organic Dirac electron candidate α-(BETS)2I3 to investigate why resistivity increases below TMI = 50 K. We found a change in carrier dynamics due to an insulating gap formation below T [...] Read more.
Photo-induced carrier dynamics were measured in the organic Dirac electron candidate α-(BETS)2I3 to investigate why resistivity increases below TMI = 50 K. We found a change in carrier dynamics due to an insulating gap formation below T = 50 K. On the other hand, the relaxation time and polarization anisotropy of the observed dynamics differ from those in the charge-ordering (CO) state of the isostructural salt α-(ET)2I3. Based on the difference, it can be concluded that the insulating phase has a different origin than the CO state. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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11 pages, 669 KiB  
Article
Gauge Theories of Josephson Junction Arrays: Why Disorder Is Irrelevant for the Electric Response of Disordered Superconducting Films
by Carlo A. Trugenberger
Condens. Matter 2023, 8(3), 85; https://doi.org/10.3390/condmat8030085 - 19 Sep 2023
Cited by 1 | Viewed by 1292
Abstract
We review the topological gauge theory of Josephson junction arrays and thin film superconductors, stressing the role of the usually forgotten quantum phase slips, and we derive their quantum phase structure. A quantum phase transition from a superconducting to the dual, superinsulating phase [...] Read more.
We review the topological gauge theory of Josephson junction arrays and thin film superconductors, stressing the role of the usually forgotten quantum phase slips, and we derive their quantum phase structure. A quantum phase transition from a superconducting to the dual, superinsulating phase with infinite resistance (even at finite temperatures) is either direct or goes through an intermediate bosonic topological insulator phase, which is typically also called Bose metal. We show how, contrary to a widely held opinion, disorder is not relevant for the electric response in these quantum phases because excitations in the spectrum are either symmetry-protected or neutral due to confinement. The quantum phase transitions are driven only by the electric interaction growing ever stronger. First, this prevents Bose condensation, upon which out-of-condensate charges and vortices form a topological quantum state owing to mutual statistics interactions. Then, at even stronger couplings, an electric flux tube dual to Abrikosov vortices induces a linearly confining potential between charges, giving rise to superinsulation. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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13 pages, 2742 KiB  
Article
Superlattices, Bonding-Antibonding, Fermi Surface Nesting, and Superconductivity
by Jose A. Alarco and Ian D. R. Mackinnon
Condens. Matter 2023, 8(3), 72; https://doi.org/10.3390/condmat8030072 - 15 Aug 2023
Cited by 1 | Viewed by 1405
Abstract
Raman and synchrotron THz absorption spectral measurements on MgB2 provide experimental evidence for electron orbital superlattices. In earlier work, we have detected THz spectra that show superlattice absorption peaks with low wavenumbers, for which spectral density evolves and intensifies after cooling below [...] Read more.
Raman and synchrotron THz absorption spectral measurements on MgB2 provide experimental evidence for electron orbital superlattices. In earlier work, we have detected THz spectra that show superlattice absorption peaks with low wavenumbers, for which spectral density evolves and intensifies after cooling below the superconducting transition temperature for MgB2. In this work, we show how these observations indicate a direct connection to superconducting properties and mechanisms. Bonding–antibonding orbital character is identified in calculated electronic band structures and Fermi surfaces consistent with superlattice structures along the c-axis. DFT calculations show that superlattice folding of reciprocal space generates Brillouin zone boundary reflections, Umklapp processes, and substantially enhances nesting relationships. Tight binding equations are compared with expected charge density waves from nesting relationships and adjusted to explicitly accommodate these linked processes. Systematic analysis of electronic band structures and Fermi surfaces allows for direct identification of Cooper pairing and the superconducting gap, particularly when the k-grid resolution of a calculation is suitably calibrated to structural parameters. Thus, we detail a robust and accurate DFT re-interpretation of BCS superconductivity for MgB2. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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9 pages, 3846 KiB  
Article
Multiband Superconductivity in High-Pressure Sulfur Hydrides
by Giovanni Alberto Ummarino and Antonio Bianconi
Condens. Matter 2023, 8(3), 69; https://doi.org/10.3390/condmat8030069 - 9 Aug 2023
Viewed by 979
Abstract
The temperature dependence of the two superconducting gaps in pressurised H3S at 155 GPa with a critical temperature of 203 K has been determined using a data analysis of the experimental curve of the upper critical magnetic field as a function [...] Read more.
The temperature dependence of the two superconducting gaps in pressurised H3S at 155 GPa with a critical temperature of 203 K has been determined using a data analysis of the experimental curve of the upper critical magnetic field as a function of temperature in the framework of the two-band s-wave Eliashberg theory. Two different phonon-mediated intra-band Cooper pairing channels in a regime of moderate strong couplings have the key role of the pair-exchange interaction between the two gaps, giving the two non-diagonal terms of the coupling tensor, which are missing in the single-band s-wave Eliashberg theory. The results provide a prediction of the different temperature dependence of the small and large gaps as a function of temperature, which provides evidence of multigap superconductivity in H3S. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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Review

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9 pages, 449 KiB  
Review
Superconductors without Symmetry Breaking
by Maria Cristina Diamantini
Condens. Matter 2024, 9(2), 21; https://doi.org/10.3390/condmat9020021 - 2 Apr 2024
Viewed by 891
Abstract
We review the main features of type-III superconductivity. This is a new type of superconductivity that exists in both 2 and 3 spatial dimensions. The main characteristics are emergent granularity and the superconducting gap being opened by a topological mechanism, with no Higgs [...] Read more.
We review the main features of type-III superconductivity. This is a new type of superconductivity that exists in both 2 and 3 spatial dimensions. The main characteristics are emergent granularity and the superconducting gap being opened by a topological mechanism, with no Higgs field involved. Superconductivity is destroyed by the proliferation of vortices and not by the breaking of Cooper pairs, which survive above the critical temperature. The hallmark of this superconductivity mechanism, in 3 spatial dimensions (3D), is the Vogel–Fulcher–Taman scaling of the resistance with temperature. Full article
(This article belongs to the Special Issue Superstripes Physics, 2nd Edition)
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