scholarly journals Can Doping Graphite Trigger Room Temperature Superconductivity? Evidence for Granular High-Temperature Superconductivity in Water-Treated Graphite Powder

2012 ◽  
Vol 24 (43) ◽  
pp. 5826-5831 ◽  
Author(s):  
T. Scheike ◽  
W. Böhlmann ◽  
P. Esquinazi ◽  
J. Barzola-Quiquia ◽  
A. Ballestar ◽  
...  
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Graphite Powder ◽  
Room Temperature Superconductivity

scholarly journals Room-temperature oxygen vacancy migration induced reversible phase transformation during the anelastic deformation in CuO

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lei Li ◽  
Guoxujia Chen ◽  
He Zheng ◽  
Weiwei Meng ◽  
Shuangfeng Jia ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxygen Vacancy ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Experimental Investigations ◽  
Solid State Chemistry ◽  
Vacancy Migration ◽  
Scientific Disciplines ◽  
Anelastic Deformation ◽  
Reversible Phase

AbstractFrom the mechanical perspectives, the influence of point defects is generally considered at high temperature, especially when the creep deformation dominates. Here, we show the stress-induced reversible oxygen vacancy migration in CuO nanowires at room temperature, causing the unanticipated anelastic deformation. The anelastic strain is associated with the nucleation of oxygen-deficient CuOx phase, which gradually transforms back to CuO after stress releasing, leading to the gradual recovery of the nanowire shape. Detailed analysis reveals an oxygen deficient metastable CuOx phase that has been overlooked in the literatures. Both theoretical and experimental investigations faithfully predict the oxygen vacancy diffusion pathways in CuO. Our finding facilitates a better understanding of the complicated mechanical behaviors in materials, which could also be relevant across multiple scientific disciplines, such as high-temperature superconductivity and solid-state chemistry in Cu-O compounds, etc.

Structure–property correlations in phase-pure B-doped Q-carbon high-temperature superconductor with a record Tc = 55 K

Nanoscale ◽  
2019 ◽  
Vol 11 (18) ◽  
pp. 9141-9154 ◽  
Author(s):  
Anagh Bhaumik ◽  
Jagdish Narayan
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
High Temperature Superconductor ◽  
Structure Property ◽  
Phase Pure ◽  
Room Temperature Superconductivity ◽  
Property Correlations

The discovery of record BCS Tc = 55 K superconductivity in phase-pure B-doped Q-carbon will provide the pathway to achieve room-temperature superconductivity.

scholarly journals Pressure-induced high-temperature superconductivity retained without pressure in FeSe single crystals

2021 ◽  
Vol 118 (28) ◽  
pp. e2108938118
Author(s):  
Liangzi Deng ◽  
Trevor Bontke ◽  
Rabin Dahal ◽  
Yu Xie ◽  
Bin Gao ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Superconductivity ◽  
Ambient Pressure ◽  
Superconducting Transition ◽  
Elastic Band ◽  
New Era ◽  
Ab Initio Simulations ◽  
Sustained Effort ◽  
Minimal Effort ◽  
Room Temperature Superconductivity

To raise the superconducting-transition temperature (Tc) has been the driving force for the long-sustained effort in superconductivity research. Recent progress in hydrides with Tcs up to 287 K under pressure of 267 GPa has heralded a new era of room temperature superconductivity (RTS) with immense technological promise. Indeed, RTS will lift the temperature barrier for the ubiquitous application of superconductivity. Unfortunately, formidable pressure is required to attain such high Tcs. The most effective relief to this impasse is to remove the pressure needed while retaining the pressure-induced Tc without pressure. Here, we show such a possibility in the pure and doped high-temperature superconductor (HTS) FeSe by retaining, at ambient pressure via pressure quenching (PQ), its Tc up to 37 K (quadrupling that of a pristine FeSe at ambient) and other pressure-induced phases. We have also observed that some phases remain stable without pressure at up to 300 K and for at least 7 d. The observations are in qualitative agreement with our ab initio simulations using the solid-state nudged elastic band (SSNEB) method. We strongly believe that the PQ technique developed here can be adapted to the RTS hydrides and other materials of value with minimal effort.

scholarly journals ELECTRON–PHONON INTERACTIONS CAUSE HTSC

2001 ◽  
Vol 15 (24n25) ◽  
pp. 3153-3155 ◽  
Author(s):  
J. C. PHILLIPS
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Light Pulses ◽  
Pressure Changes

What is the microscopic interaction responsible for high temperature superconductivity (HTSC)? Here data on temporal relaxation of T c and the room temperature conductivity in YBa2Cu3O 6+x after abrupt alteration by light pulses or pressure changes are analyzed. The analysis proves, independently of microscopic details, that only electron–phonon interactions can cause HTSC in the cuprates; all other dynamical interactions are excluded by experiment.

Induction of high-temperature superconductivity in pulsed laser ablated La2CuO4thin films by room temperature chemical oxidation

1997 ◽  
Vol 9 (10) ◽  
pp. 823-826 ◽  
Author(s):  
Simon T. Lees ◽  
Peter P. Edwards ◽  
Ian Gameson ◽  
Martin O. Jones ◽  
Marcin Slaski ◽  
...  
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Pulsed Laser ◽  
Chemical Oxidation

Cuprate High Temperature Superconductors and the Vision for Room Temperature Superconductivity

SPIN ◽  
2017 ◽  
Vol 07 (02) ◽  
pp. 1750006 ◽  
Author(s):  
Dennis M. Newns ◽  
Glenn J. Martyna ◽  
Chang C. Tsuei
Keyword(s):  
High Temperature ◽  
High Frequency ◽  
Room Temperature ◽  
Phonon Frequency ◽  
High Temperature Superconductors ◽  
Low Frequency ◽  
Unconventional Superconductivity ◽  
Superconducting Transition ◽  
Strongly Coupled ◽  
Room Temperature Superconductivity

Superconducting transition temperatures of 164 K in cuprate high temperature superconductors (HTS) and recently 200 K in H3S under high pressure encourage us to believe that room temperature superconductivity (RTS) might be possible. In considering paths to RTS, we contrast conventional (BCS) SC, such as probably manifested by H3S, with the unconventional superconductivity (SC) in the cuprate HTS family. Turning to SC models, we show that in the presence of one or more van Hove singularities (vHs) near the Fermi level, SC mediated by classical phonons ([Formula: see text]phonon frequency) can occur. The phonon frequency in the standard [Formula: see text] formula is replaced by an electronic cutoff, enabling a much higher [Formula: see text] independent of phonon frequency. The resulting [Formula: see text] and isotope shift plot versus doping strongly resembles that seen experimentally in HTS. A more detailed theory of HTS, which involves mediation by classical phonons, satisfactorily reproduces the chief anomalous features characteristic of these materials. We propose that, while a path to RTS through an H3S-like scenario via strongly-coupled ultra-high frequency phonons is attractive, features perhaps unavailable at ordinary pressures, a route involving SC mediated by classical phonons which can be low frequency may be found.

The Formation of Cooper Pairs and their Role in Nondissipative Diamagnetic Currents in the Micro- and Macro-Scopic Sized Graphene Materials; Towards High-Temperature Superconductivity

2014 ◽  
Vol 918 ◽  
pp. 36-41
Author(s):  
Takashi Kato
Keyword(s):  
High Temperature ◽  
Experimental Research ◽  
High Temperature Superconductivity ◽  
Hydrogen Plasma ◽  
Graphite Powder ◽  
Cooper Pairs ◽  
Coulomb Interactions ◽  
Solid State Physics ◽  
Previous Theory ◽  
Homo Lumo

The mechanism of the formation of Cooper pairs and their role in the occurrence of nondissipative diamagnetic currents is investigated. In the previous works [1-, we suggested that in the materials with large HOMO-LUMO gaps (ΔEHOMO-LUMO,N), the Cooper pairs are formed by the large HOMO-LUMO gaps as a consequence of the quantization of the orbitals by nature, and by the attractive Coulomb interactions between two electrons with opposite momentum and spins occupying the same orbitals via the positively charged nuclei. On the other hand, according to the recent experimental research [, the Cooper pairs have been observed at room temperatures in the neutral benzene (6an), naphthalene (10ac), anthracene (14ac), and coronene molecules. That is, our prediction in our theoretical researches [1-can be well confirmed by the recent experimental research [, and our previous theory can be reasonably applied to the explanation of the mechanism of the occurrence of the granular high temperature superconductivity in carbon materials [. We show that the forming of Cooper pairs [ can be well explained by our theory previously suggested [1-. We also suggest the reasonable mechanism of the occurrence of granular high temperature superconductivity in the graphite powder treated by water or exposed to the hydrogen plasma, discovered by Esquinazi et al. [, on the basis of our previous theoretical works described above [1-, which can be well confirmed by the recent experimental work [. We also suggest the general guiding principle towards high temperature superconductivity. We suggest that any material with large ΔEHOMO-LUMO,N value (more than a few eV), in which valence bands are completely occupied by electrons, which has been believed to be typical insulator in view of solid state physics and chemistry, has a possibility to exhibit high temperature superconductivity in solids.

Itinerant Vibrons and High-Temperature Superconductivity*

2000 ◽  
Vol 658 ◽  
Author(s):  
John B. Goodenough
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Phase Segregation ◽  
Optical Mode ◽  
Temperature Changes ◽  
Critical Composition ◽  
Underdoped Region ◽  
Small Polarons ◽  
Electronic Behavior

ABSTRACTThe La2−xSrxCuO4 phase diagram is interpreted within the framework of a transition from localized to itinerant electronic behavior. In the underdoped region 0 < x < 0.1, holes in the x2 – y2 band are not small polarons; each occupies a mobile correlation bag of 5 to 6 copper centers at temperatures T > TF, a spinodal phase segregation into the parent antiferromagnetic phase and a polaron liquid is accomplished below TF by cooperative oxygen displacements. In the overdoped compositions > x > 0.25, holes are excluded from strong-correlation fluctuations within a Fermi liquid. In the intermediate range 0.1 < x < 0.25, the polaron liquid formed below room temperature changes character with increasing x and decreasing T. In the polaron liquid, mobile two-hole bags of four copper centers order with decreasing temperature into alternate CuO-Cu rows of a superconductive CuO2 sheet at a critical composition xc ≍ 1/6. It is argued that hybridization of itinerant electrons with optical-mode phonons propagating along the Cu-O-Cu rows produces heavy electrons responsible for high-temperature superconductivity.

scholarly journals The Needle in the Haystack for Theory of High Temperature Superconductivity: Negative Nuclear Magnetic Moments

2018 ◽  
Author(s):  
Reginald Little
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Cooper Pair ◽  
High Temperature Superconductivity ◽  
Magnetic Moments ◽  
High Energy ◽  
Cooper Pairs ◽  
Nuclear Magnetic Moments ◽  
Relativistic Scattering ◽  
Nuclear Magnetic

This work outlines a theory for explaining high temperature superconductivity on the basis of relativistic scattering of Cooper pairs via beyond room temperature conditions causing high energy relativistic scattering of Cooper pairs with nuclei having positive and negative nuclear magnetic moments for fractionally reversibly fissing and fusing the nuclei for manifesting in the electronic lattice for altered quantum fields for more tightly binding the Cooper pair beyond the conventional critical temperature 40K limit for superconductivity beyond room temperature.

scholarly journals The Needle in the Haystack for Theory of High Temperature Superconductivity: Negative Nuclear Magnetic Moments

2018 ◽  
Author(s):  
Reginald Little
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Cooper Pair ◽  
High Temperature Superconductivity ◽  
Magnetic Moments ◽  
High Energy ◽  
Cooper Pairs ◽  
Nuclear Magnetic Moments ◽  
Relativistic Scattering ◽  
Nuclear Magnetic

This work outlines a theory for explaining high temperature superconductivity on the basis of relativistic scattering of Cooper pairs via beyond room temperature conditions causing high energy relativistic scattering of Cooper pairs with nuclei having positive and negative nuclear magnetic moments for fractionally reversibly fissing and fusing the nuclei for manifesting in the electronic lattice for altered quantum fields for more tightly binding the Cooper pair beyond the conventional critical temperature 40K limit for superconductivity beyond room temperature.

Sign in / Sign up

Export Citation Format

Share Document