Femtosecond Pump-probe studies of Carrier Dynamics in the Normal State of the Unconventional Superconductor Sr2RuO4

2004 ◽  
Vol 850 ◽  
Author(s):  
P. Guptasarma ◽  
S. L. Sendelbach ◽  
M. L. Schneider ◽  
M. S. Williamsen ◽  
G. Taft ◽  
...  
Keyword(s):  
Normal State ◽  
Superconducting State ◽  
Condensed Matter ◽  
Carrier Dynamics ◽  
Unconventional Superconductivity ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Unconventional Superconductor ◽  
Pump Probe ◽  
Microscopic Origin

The microscopic origin of unconventional superconductivity1 is one of the most fascinating questions2–3 in condensed matter physics. In recent years, important questions have been raised about the nature of the normal (metallic, non-superconducting) state above the superconducting critical transition temperature (Tc). In fact, it is now generally agreed4,5 that a better understanding of the nature of the normal state is crucial to our understanding of the microscopic origin of the superconducting state.

UNCONVENTIONAL SUPERCONDUCTIVITY IN UPt3: FREQUENCY DEPENDENT AC SUSCEPTIBILITY

1993 ◽  
Vol 07 (01n03) ◽  
pp. 18-21
Author(s):  
Z. KOZIOL ◽  
J. J. M. FRANSE ◽  
A. A. MENOVSKY
Keyword(s):  
Normal State ◽  
Surface Resistance ◽  
Skin Effect ◽  
Ac Susceptibility ◽  
Response Characteristic ◽  
Complex Conductivity ◽  
Unconventional Superconductivity ◽  
Superconducting Transition ◽  
Good Qualitative Agreement ◽  
Unconventional Superconductor

A method has been developed for measuring and analysing the complex ac susceptibility of a metal undergoing a superconducting transition, in case there exists an interplay between the normal-state skin-effect and the response characteristic for the superconducting state. For the unconventional superconductor UPt 3, the study of the temperature and frequency dependence of the complex conductivity close to T c has resulted in predictions for the surface resistance and the radio-frequency susceptibility which are in a good qualitative agreement with published experimental results.

scholarly journals Information-theoretic measures of superconductivity in a two-dimensional doped Mott insulator

2021 ◽  
Vol 118 (25) ◽  
pp. e2104114118
Author(s):  
Caitlin Walsh ◽  
Maxime Charlebois ◽  
Patrick Sémon ◽  
Giovanni Sordi ◽  
André-Marie S. Tremblay
Keyword(s):  
Normal State ◽  
Superconducting State ◽  
Mean Field Theory ◽  
Mott Insulator ◽  
Two Dimensional ◽  
Local Entropy ◽  
Unconventional Superconductor ◽  
Doped Mott Insulator ◽  
Classical Correlations ◽  
Quantum And Classical Correlations

A key open issue in condensed-matter physics is how quantum and classical correlations emerge in an unconventional superconductor from the underlying normal state. We study this problem in a doped Mott insulator with information-theory tools on the two-dimensional (2D) Hubbard model at finite temperature with cluster dynamical mean-field theory. We find that the local entropy detects the superconducting state and that the difference in the local entropy between the superconducting and normal states follows the same difference in the potential energy. We find that the thermodynamic entropy is suppressed in the superconducting state and monotonically decreases with decreasing doping. The maximum in entropy found in the normal state above the overdoped region of the superconducting dome is obliterated by superconductivity. The total mutual information, which quantifies quantum and classical correlations, is amplified in the superconducting state of the doped Mott insulator for all doping levels and shows a broad peak versus doping, as a result of competing quantum and classical effects.

scholarly journals Giant Photoluminescence Enhancement and Carrier Dynamics in MoS2 Bilayers with Anomalous Interlayer Coupling

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1994
Author(s):  
Han Li ◽  
Yating Ma ◽  
Zhongjie Xu ◽  
Xiang’ai Cheng ◽  
Tian Jiang
Keyword(s):  
Optical Properties ◽  
Transition Metal Dichalcogenides ◽  
Interlayer Coupling ◽  
Carrier Dynamics ◽  
Probe Signal ◽  
Exciton Resonance ◽  
Pump Probe ◽  
Metal Dichalcogenides ◽  
Photoluminescence Enhancement ◽  
Probe Measurements

Fundamental researches and explorations based on transition metal dichalcogenides (TMDCs) mainly focus on their monolayer counterparts, where optical densities are limited owing to the atomic monolayer thickness. Photoluminescence (PL) yield in bilayer TMDCs is much suppressed owing to indirect-bandgap properties. Here, optical properties are explored in artificially twisted bilayers of molybdenum disulfide (MoS2). Anomalous interlayer coupling and resultant giant PL enhancement are firstly observed in MoS2 bilayers, related to the suspension of the top layer material and independent of twisted angle. Moreover, carrier dynamics in MoS2 bilayers with anomalous interlayer coupling are revealed with pump-probe measurements, and the secondary rising behavior in pump-probe signal of B-exciton resonance, originating from valley depolarization of A-exciton, is firstly reported and discussed in this work. These results lay the groundwork for future advancement and applications beyond TMDCs monolayers.

Correlation between oxygen excess density and critical transition temperature in superconducting Bi-2201, Bi-2212 and Bi-2223

2008 ◽  
Vol 63 (11-12) ◽  
pp. 1372-1375 ◽  
Author(s):  
H.P. Roeser ◽  
F. Hetfleisch ◽  
F.M. Huber ◽  
M.F. von Schoenermark ◽  
M. Stepper ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Excess Density ◽  
Oxygen Excess

Critical current density and microstructure variations in YBa2Cu3O7−x + BaSnO3 films with different concentrations of BaSnO3

2008 ◽  
Vol 23 (12) ◽  
pp. 3363-3369 ◽  
Author(s):  
C.V. Varanasi ◽  
J. Burke ◽  
L. Brunke ◽  
H. Wang ◽  
J.H. Lee ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Gradual Increase ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
High Fields ◽  
Magnitude Increase

Previous work on YBa2Cu3O7−x (YBCO) + BaSnO3 (BSO) films with a single composition showed significant critical current density (Jc) improvements at higher fields but lowered Jc in low fields. A detailed study on BSO concentrations provided here demonstrates that significant Jc enhancement can occur even up to 20 mol% BSO inclusion, where typical particulate inclusions in these concentrations degrade the YBCO performance. YBCO + BSO films were processed on (100) LaAlO3 substrates using premixed targets of YBa2Cu3O7-x (YBCO) with additions of 2, 4, 10, and 20 mol% BSO. The critical transition temperature Tc of the films remained high (>87 K), even with large amounts (20 mol%) of BSO. YBCO + BSO films showed a gradual increase in Jc at high fields as the amount of BSO was increased. More than an order of magnitude increase in Jc was measured in YBCO + BSO samples as compared to regular YBCO at 4 T. YBCO + 10 mol% BSO films showed overall improvement at all the field ranges while YBCO + 20 mol% BSO was better only at high fields. Transmission electron microscopy revealed the presence of ∼7–8-nm-diameter BSO nanocolumns, the density of which increased with increasing BSO content correlating well with the observed improvements in Jc.

Measurement of parameters of the superconducting non-insulated coils

2021 ◽  
pp. 41-46
Author(s):  
Evgeniy P. Krasnoperov ◽  
Valentin V. Guryev ◽  
Vasyli V. Sychugov ◽  
Dmitri S. Yashkin ◽  
Sergei V. Shavkin
Keyword(s):  
Normal State ◽  
Superconducting State ◽  
Critical Value ◽  
Magnetic Characteristics ◽  
Electrical Characteristics ◽  
Linear Current ◽  
Superconducting Coils ◽  
Current Voltage ◽  
Current Input

The electrical characteristics of superconducting coils with non-insulated windings are studied. The procedures for measuring the parameters of uninsulated superconducting windings are described. In particular, the inductance is measured by voltage with a linear current input at a given rate. Attention is focused on the impossibility of correctly determining the inductance in a winding with an uninsulated superconductor in a normal state. It is noted that in a superconducting state at currents below the critical value, the inductance of the winding is comparable to the inductance with an insulated wire. The results of measurements of inductance, radial resistance, static current-voltage and magnetic characteristics of two tape coils with non-insulated superconducting windings, one of which had a soldered connection, are presented. Conditions for measuring the parameters of non-insulated superconducting windings are formulated when they are compared with insulated windings.

Ultrafast Pump-Probe Reflectivity Study of Carrier Dynamics in Silicon Surface

2008 ◽  
Vol 35 (9) ◽  
pp. 1365-1369 ◽  
Author(s):  
刘国栋 Liu Guodong ◽  
王贵兵 Wang Guibing ◽  
付博 Fu Bo ◽  
江继军 Jiang Jijun ◽  
王伟平 Wang Weiping ◽  
...  
Keyword(s):  
Silicon Surface ◽  
Carrier Dynamics ◽  
Pump Probe

scholarly journals Observation of half-quantum flux in the unconventional superconductor β-Bi2Pd

Science ◽  
2019 ◽  
Vol 366 (6462) ◽  
pp. 238-241 ◽  
Author(s):  
Yufan Li ◽  
Xiaoying Xu ◽  
M.-H. Lee ◽  
M.-W. Chu ◽  
C. L. Chien
Keyword(s):  
Magnetic Flux ◽  
Pairing Symmetry ◽  
Quantum Oscillation ◽  
Unconventional Superconductivity ◽  
Unconventional Superconductor ◽  
Quantum Bits ◽  
Flux Quantization ◽  
Triplet Pairing ◽  
Quantum Flux ◽  
Spin Triplet

Magnetic flux quantization is one of the defining properties of a superconductor. We report the observation of half-integer magnetic flux quantization in mesoscopic rings of superconducting β-Bi2Pd thin films. The half-quantum fluxoid manifests itself as a π phase shift in the quantum oscillation of the superconducting critical temperature. This result verifies unconventional superconductivity of β-Bi2Pd and is consistent with a spin-triplet pairing symmetry. Our findings may have implications for flux quantum bits in the context of quantum computing.

Reformulation of pairing theory

1988 ◽  
Vol 02 (05) ◽  
pp. 1101-1105 ◽  
Author(s):  
Miklos GULACSI ◽  
Zsolt GULACSI
Keyword(s):  
Transition Temperature ◽  
Size Effect ◽  
Layer Thickness ◽  
Short Communication ◽  
Cooper Pairing ◽  
Two Dimensional ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Quantum Size ◽  
Natural Way

The original Cooper pairing theory is reformulated for electrons confined in a layer. This analysis is motivated by the quasi-two-dimensional character of the oxidic superconductors, in case of which the extension of the initial (3D) Cooper framework is practically impossible. By considering the electrons moving in a flat box, due to quantum size effect the properties of these oxidic superconductors can be explained in a natural way. In this short communication we will concentrate to the variation of the critical transition temperature due to the layer thickness and to the number of conduction (Cu-O) planes. The results are confirmed by the experiment. This being an evidence for the presence of the charge confinement effect in the oxidic superconductors.

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