Superstripes Physics

A special issue of Condensed Matter (ISSN 2410-3896). This special issue belongs to the section "Quantum Materials".

Deadline for manuscript submissions: closed (28 February 2023) | Viewed by 14865

Special Issue Editors

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
Special Issues, Collections and Topics in MDPI journals
1. INFN–LNF, Via E. Fermi 54, 00044 Frascati, Italy
2. CNR - Istituto Struttura della Materia and Elettra-Sincrotrone Trieste, Basovizza Area Science Park, 34149 Trieste, Italy
3. RICMASS - Rome International Center for Materials Science – Superstripes, Via dei Sabelli 119A, 00185 Roma, Italy
Interests: correlation phenomena in X-ray absorption spectroscopy; X-ray absorption in elements of geophysical interest; dust and aerosol characterization; ultra-trace detection for indoor and outdoor environmental studies
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue will publish selected papers from the Superstripes 2022 meeting due to take place 20–24 June 2022 in Frascati, Italy. The aim of the 2022 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. Papers should focus on the following research subfields:

  1. Superstripes, Supersolids, Supercrystals, and Supermetals;
  2. Charge-density waves, spin-density waves, and periodic local lattice distortions;
  3. Inhomogeneity of CDW order, SDW order and local lattice distortions;
  4. Puddle formation, multiscale texture;
  5. Multi-band superconductivity, multi-orbital superconductivity multi-gap superconductivity, two-gap superconductivity;
  6. Complexity in correlated electron systems (Mott transition, quantum criticality, multi-band Hubbard model);
  7. Lifshitz transitions;
  8. Fano Feshbach Resonances, BEC–BCS crossover;
  9. Unconventional electron–phonon interaction;
  10. Strain;
  11. Edge states;
  12. Spin–orbit interaction;
  13. Rashba physics and topological order;
  14. Spintronics (Skyrmions, itinerant electron magnetism, spin current, magnetic memory);
  15. Topological quantum science, and topological materials;
  16. Topology and ferromagnets;
  17. Coexistence of magnetism and superconductivity;
  18. Ultracold atoms;
  19. High-pressure physics;
  20. Superconducting pressurized hydrides;
  21. Room temperature superconductivity;
  22. New features of Stripe-order in cuprates and related materials;
  23. Complex quantum matter;
  24. Nanoscale phase separation;
  25. Magnetic field control of stripes-order;
  26. Uniaxial Stress control of stripes-order;
  27. High-entropy materials;
  28. Moiré materials;
  29. Over-doped cuprates;
  30. Spectroscopy from terahertz to X-rays;
  31. Twisted bilayer graphene, twisted 2D flakes;
  32. Physics and technology of 2D flakes.

Prof. Dr. Antonio Bianconi
Prof. Dr. Augusto Marcelli
Guest Editors

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Published Papers (10 papers)

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Research

10 pages, 1900 KiB  
Article
Tc Saturation and Possible Electronic Phase Separation in Strongly Overdoped Cuprates
by Amirreza Hemmatzade, Elena Medina, Ludovic Delbes, Benoît Baptiste, David Hrabovsky, Yannick Klein, Steven D. Conradson, Maarit Karppinen and Andrea Gauzzi
Condens. Matter 2023, 8(3), 56; https://doi.org/10.3390/condmat8030056 - 05 Jul 2023
Viewed by 823
Abstract
In order to elucidate the unusual superconducting properties of cuprates in the strongly overdoped region, i.e., at hole-doping levels p0.4/Cu in the CuO2 plane, we study the structural and superconducting properties of a series of Cu0.75Mo0.25 [...] Read more.
In order to elucidate the unusual superconducting properties of cuprates in the strongly overdoped region, i.e., at hole-doping levels p0.4/Cu in the CuO2 plane, we study the structural and superconducting properties of a series of Cu0.75Mo0.25Sr2YCu2O7+x powder samples oxygenated under high pressure using different concentrations of KClO3 up to 35 mol %. The analysis of X-ray diffraction data indicates a high purity ∼90% of all samples and suggests that the concentration, x, of extra oxygen atoms increases with increasing KClO3 concentration. Surprisingly, the Tc values remain nearly constant within the 80–85 K range independent of KClO3 concentration, which suggests a scenario of Tc saturation. In order to account for this unexpected behaviour, we put forward the hypothesis that overdoping enhances the density of unpaired holes, which is supported by the observation of large values of the Sommerfeld coefficient in all samples. We therefore propose a scenario of electronic phase separation between normal and superconducting holes. Full article
(This article belongs to the Special Issue Superstripes Physics)
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9 pages, 1467 KiB  
Article
Investigating the Intrinsic Anisotropy of VO2(101) Thin Films Using Linearly Polarized Resonant Photoemission Spectroscopy
by Alessandro D’Elia, Vincent Polewczyk, Aleksandr Yu. Petrov, Liang Li, Chongwen Zou, Javad Rezvani and Augusto Marcelli
Condens. Matter 2023, 8(2), 40; https://doi.org/10.3390/condmat8020040 - 26 Apr 2023
Viewed by 1184
Abstract
VO2 is one of the most studied vanadium oxides because it undergoes a reversible metal-insulator transition (MIT) upon heating with a critical temperature of around 340 K. One of the most overlooked aspects of VO2 is the band’s anisotropy in the [...] Read more.
VO2 is one of the most studied vanadium oxides because it undergoes a reversible metal-insulator transition (MIT) upon heating with a critical temperature of around 340 K. One of the most overlooked aspects of VO2 is the band’s anisotropy in the metallic phase when the Fermi level is crossed by two bands: π* and d||. They are oriented perpendicularly in one respect to the other, hence generating anisotropy. One of the parameters tuning MIT properties is the unbalance of the electron population of π* and d|| bands that arise from their different energy position with respect to the Fermi level. In systems with reduced dimensionality, the electron population disproportion is different with respect to the bulk leading to a different anisotropy. Investigating such a system with a band-selective spectroscopic tool is mandatory. In this manuscript, we show the results of the investigation of a single crystalline 8 nm VO2/TiO2(101) film. We report on the effectiveness of linearly polarized resonant photoemission (ResPES) as a band-selective technique probing the intrinsic anisotropy of VO2. Full article
(This article belongs to the Special Issue Superstripes Physics)
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10 pages, 712 KiB  
Article
Possible Manifestation of Q-Ball Mechanism of High-Tc Superconductivity in X-ray Diffraction
by Sergei Mukhin
Condens. Matter 2023, 8(1), 16; https://doi.org/10.3390/condmat8010016 - 28 Jan 2023
Cited by 3 | Viewed by 1222
Abstract
It is demonstrated, that recently proposed by the author Q-ball mechanism of the pseudogap state and high-Tc superconductivity in cuprates may be detected in micro X-ray diffraction, since it imposes inverse correlations between the size and scattering intensities of the Q-ball charge-density-wave (CDW) [...] Read more.
It is demonstrated, that recently proposed by the author Q-ball mechanism of the pseudogap state and high-Tc superconductivity in cuprates may be detected in micro X-ray diffraction, since it imposes inverse correlations between the size and scattering intensities of the Q-ball charge-density-wave (CDW) fluctuations in these compounds. The Q-ball charge Q gives the number of condensed elementary bosonic excitations in a CDW fluctuation of finite amplitude. The attraction between these excitations inside Euclidean Q-balls is self-consistently triggered by the simultaneous condensation of Cooper/local pairs. Euclidean Q-ball solutions, analogous to the famous Q-balls of squarks in the supersymmetric standard model, arise due to the global invariance of the effective theory under the U(1) phase rotation of the Fourier amplitudes of the short-range CDW fluctuations. A conserved ‘Noether charge’ Q along the Matsubara time axis equals QTM2V, where the temperature T, Q-ball’s volume V, and fluctuation amplitude M enter. Several predictions are derived in an analytic form that follow from this picture. The conservation of the charge Q leads to an inverse proportionality between the volume V and X-ray scattering intensity ∼M2 of the CDW puddles found in micro X-ray scattering experiments. The theoretical temperature dependences of the most probable Q value of superconducting Q-balls and their size and scattering amplitudes fit well the recent X-ray diffraction data in the pseudogap phase of high-Tc cuprates. Full article
(This article belongs to the Special Issue Superstripes Physics)
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10 pages, 1777 KiB  
Article
Q-Balls in the Pseudogap Phase of Superconducting HgBa2CuO4+y
by Gaetano Campi, Luisa Barba, Nikolai D. Zhigadlo, Andrey A. Ivanov, Alexey P. Menushenkov and Antonio Bianconi
Condens. Matter 2023, 8(1), 15; https://doi.org/10.3390/condmat8010015 - 28 Jan 2023
Cited by 3 | Viewed by 1769
Abstract
Fast and local probes, such as X-ray spectroscopy, X-ray diffraction (XRD), and X-ray microscopy, have provided direct evidence for nanoscale phase separation in high temperature perovskite superconductors composed of (i) free particles coexisting with (ii) Jahn Teller polarons (i.e., charges associated with local [...] Read more.
Fast and local probes, such as X-ray spectroscopy, X-ray diffraction (XRD), and X-ray microscopy, have provided direct evidence for nanoscale phase separation in high temperature perovskite superconductors composed of (i) free particles coexisting with (ii) Jahn Teller polarons (i.e., charges associated with local lattice distortions) not detected by slow experimental methods probing only delocalized states. Moreover, these experimental probes have shown the formation of a superstripes phase in the pseudogap regime below T* in cuprates. Here, we focus on the anomalous temperature dependence of short range X-ray diffraction CDW reflection satellites with high momentum transfer, probing both charge and lattice fluctuations in superconducting HgBa2CuO4+y (Hg1201) in the pseudogap regime below T* and above Tc. We report compelling evidence of the anomalous anticorrelation of the coherence volume with the peak maximum amplitude of the CDW XRD satellite by cooling below T*. This anomalous temperature trend of the short-range striped Jahn Teller polaronic CDW puddles is in agreement with predictions of the Q-ball theory of the quark gluon plasma extended to cuprates, providing compelling evidence for non topological soliton puddles of striped condensate of pairs in the pseudogap phase. Full article
(This article belongs to the Special Issue Superstripes Physics)
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10 pages, 2725 KiB  
Article
Experimental and Theoretical Investigation of High-Resolution X-ray Absorption Spectroscopy (HR-XAS) at the Cu K-Edge for Cu2ZnSnSe4
by Wei Xu, Yujun Zhang, Kenji Ishii, Hiroki Wadati, Yingcai Zhu, Zhiying Guo, Qianshun Diao, Zhen Hong, Haijiao Han and Lidong Zhao
Condens. Matter 2023, 8(1), 8; https://doi.org/10.3390/condmat8010008 - 13 Jan 2023
Viewed by 1792
Abstract
Energy sustainability is critical for social activities in the human world. The quaternary compound Cu2ZnSnSe4 (CZTSe), as a promising candidate for thin-film solar cell absorption with medium-level thermoelectric performance, is of interest for the purpose of utilizing solar energy. The [...] Read more.
Energy sustainability is critical for social activities in the human world. The quaternary compound Cu2ZnSnSe4 (CZTSe), as a promising candidate for thin-film solar cell absorption with medium-level thermoelectric performance, is of interest for the purpose of utilizing solar energy. The defect chemistry and atomic ordering in this particular compound also triggers interests in understanding its crystallographic structure as well as defects. Hereby, high energy resolution X-ray absorption spectroscopy is employed to investigate the electronic and geometric structural complexity in pristine and cobalt-doped Cu2ZnSnSe4. The occupational atomic sites of Cu are found to be mixed with the Zn atoms, forming CuZn anti-defects, which serve as a knob to tune local electronic structures. With proper doping, the band structure can be manipulated to improve the optical and thermoelectric properties of the CZTSe compounds. Full article
(This article belongs to the Special Issue Superstripes Physics)
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8 pages, 2149 KiB  
Article
Charge–Phase Duality and Cotunneling of Fluxons in SQUID-like Nanorings
by Alex Latyshev, Andrew G. Semenov and Andrei D. Zaikin
Condens. Matter 2023, 8(1), 5; https://doi.org/10.3390/condmat8010005 - 31 Dec 2022
Viewed by 1231
Abstract
Employing charge–flux duality for Josephson junctions and superconducting nanowires, we predict a novel effect of fluxon cotunneling in SQUID-like nanorings. This process is strictly dual to that of Cooper pair cotunneling in superconducting transistors formed by a pairs of Josephson tunnel junctions connected [...] Read more.
Employing charge–flux duality for Josephson junctions and superconducting nanowires, we predict a novel effect of fluxon cotunneling in SQUID-like nanorings. This process is strictly dual to that of Cooper pair cotunneling in superconducting transistors formed by a pairs of Josephson tunnel junctions connected in series. Cooper pair cotunneling is known to lift Coulomb blockade in these structures at low temperatures. Likewise, fluxon cotunneling may eliminate the magnetic blockade of superconducting phase fluctuations in SQUID-like nanorings, driving them into an insulating state. Full article
(This article belongs to the Special Issue Superstripes Physics)
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18 pages, 2719 KiB  
Article
Destructive Interference of the Superconducting Subband Condensates in the Quasi-1D Multigap Material Nanostructures
by Wojciech Julian Pasek, Marcos Henrique Degani and Marcelo Zoéga Maialle
Condens. Matter 2023, 8(1), 4; https://doi.org/10.3390/condmat8010004 - 28 Dec 2022
Viewed by 1526
Abstract
This modelling work concerns the effects of the interference between two partial subband condensates in a quasi-one-dimensional superconducting superlattice. The iterative under-relaxation with phase control method is used to solve Bogoliubov–de Gennes equations in the envelope ansatz. This method—easily generalisable to a wide [...] Read more.
This modelling work concerns the effects of the interference between two partial subband condensates in a quasi-one-dimensional superconducting superlattice. The iterative under-relaxation with phase control method is used to solve Bogoliubov–de Gennes equations in the envelope ansatz. This method—easily generalisable to a wide class of multiband superconducting systems—allows us to obtain both the constructive and the destructive interference solution. The discussion is centred on the latter case, with one of the condensates collapsing with increased inter-subband coupling strength, due to the other—the dominating one—imposing its symmetry on the overall order parameter. The in-depth qualitative analysis is made of underlying intra-subband and inter-subband dynamics, such as the possible factors determining the dominant subband condensate or the ones determining the region where the destructive solution coexists with the constructive one. A comprehensive discussion with the recent works concerning inter-band coupling effects follows, pointing that the destructive solution is nearly universally omitted. Full article
(This article belongs to the Special Issue Superstripes Physics)
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12 pages, 6776 KiB  
Article
Polarons in Rock-Forming Minerals: Physical Implications
by Boriana Mihailova, Giancarlo Della Ventura, Naemi Waeselmann, Simone Bernardini, Wei Xu and Augusto Marcelli
Condens. Matter 2022, 7(4), 68; https://doi.org/10.3390/condmat7040068 - 16 Nov 2022
Cited by 2 | Viewed by 1471
Abstract
The existence of thermally-activated quasiparticles in amphiboles is an important issue, as amphiboles are among the main hydrous complex silicate minerals in the Earth’s lithosphere. The amphibole structure consists of stripes of 6-membered TO4-rings sandwiching MO6 octahedral slabs. To elucidate [...] Read more.
The existence of thermally-activated quasiparticles in amphiboles is an important issue, as amphiboles are among the main hydrous complex silicate minerals in the Earth’s lithosphere. The amphibole structure consists of stripes of 6-membered TO4-rings sandwiching MO6 octahedral slabs. To elucidate the atomistic origin of the anomalous rock conductivity in subduction-wedge regions, we studied several Fe-containing amphiboles with diverse chemistry by using in situ, temperature-dependent, polarised Raman spectroscopy. The occurrence of resonance Raman scattering at high temperatures unambiguously reveal temperature-activated small polarons arising from the coupling between polar optical phonons and electron transitions within Fe2+O6 octahedra, independently of the amphibole chemical composition. The FeO6-related polarons coexist with delocalised H+; that is, at elevated temperatures Fe-bearing amphiboles are conductive and exhibit two types of charge carriers: electronic polarons with highly anisotropic mobility and H+ cations. The results from density-functional-theory calculations on the electron band structure for a selected amphibole compound with a relatively simple composition are in full agreement with experimental data. The polaron activation temperature, mobility, and polaron-dipole magnitude and alignment can be controlled by varying the mineral composition, which makes amphiboles attractive “geo-stripes” that can serve as mineral-inspired technology to design thermally-stable smart materials with anisotropic properties. Full article
(This article belongs to the Special Issue Superstripes Physics)
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12 pages, 10373 KiB  
Article
Magnetic Interaction in Doped 2D Perovskite Cuprates with Nanoscale Inhomogeneity: Lattice Nonlocal Effects vs. Superexchange
by Vladimir A. Gavrichkov and Semyon I. Polukeev
Condens. Matter 2022, 7(4), 57; https://doi.org/10.3390/condmat7040057 - 18 Oct 2022
Cited by 3 | Viewed by 1479
Abstract
We have studied the superexchange interaction Jij in doped 2D cuprates. The AFM interaction strongly depends on the state of the lattice of a CuO2 layer surrounded by two LaO rock salt layers. In a static U and D [...] Read more.
We have studied the superexchange interaction Jij in doped 2D cuprates. The AFM interaction strongly depends on the state of the lattice of a CuO2 layer surrounded by two LaO rock salt layers. In a static U and D stripe nanostructure, the homogeneous AFM interaction is impossible due to the U/D/U periodic stripe sequence and TN=0. In a dynamic stripe nanostructure, the ideal CuO2 layer with nonlocal effects and the homogeneous AFM interaction are restored. However, the interaction Jij decreases by the exponential factor due to partial dynamic quenching. The meaning of the transition from the dynamic to the static cases lies in the spontaneous θ-symmetry breaking with respect to the rotation of all the tilted CuO6 octahedra by an orientation angle δθ=n·45° (where n=1÷4) in the U and D stripe nanostructure of the CuO2 layer. Moreover, the structural features help to study various experimental data on the charge inhomogeneity, Fermi level pinning in the p type cuprates only and time reversal symmetry breaking from a unified point of view. Full article
(This article belongs to the Special Issue Superstripes Physics)
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10 pages, 1650 KiB  
Article
Scale-Free Distribution of Oxygen Interstitial Wires in Optimum-Doped HgBa2CuO4+y
by Gaetano Campi, Maria Vittoria Mazziotti, Thomas Jarlborg and Antonio Bianconi
Condens. Matter 2022, 7(4), 56; https://doi.org/10.3390/condmat7040056 - 12 Oct 2022
Cited by 1 | Viewed by 1498
Abstract
Novel nanoscale probes are opening new venues for understanding unconventional electronic and magnetic functionalities driven by multiscale lattice complexity in doped high-temperature superconducting perovskites. In this work, we focus on the multiscale texture at supramolecular level of oxygen interstitial (O-i) atomic stripes in [...] Read more.
Novel nanoscale probes are opening new venues for understanding unconventional electronic and magnetic functionalities driven by multiscale lattice complexity in doped high-temperature superconducting perovskites. In this work, we focus on the multiscale texture at supramolecular level of oxygen interstitial (O-i) atomic stripes in HgBa2CuO4+y at optimal doping for the highest superconducting critical temperature (TC) of 94 K. We report compelling evidence for the nematic phase of oxygen interstitial O-i atomic wires with fractal-like spatial distribution over multiple scales using scanning micro- and nano-X-ray diffraction. The scale-free distribution of O-i atomic wires at optimum doping extending from the micron down to the nanoscale has been associated with the intricate filamentary network of hole-rich metallic wires in the CuO2 plane. The observed critical opalescence provides evidence for the proximity to a critical point that controls the emergence of high-temperature superconductivity at optimum doping. Full article
(This article belongs to the Special Issue Superstripes Physics)
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