Bulletin of the American Physical Society
APS March Meeting 2019
Volume 64, Number 2
Monday–Friday, March 4–8, 2019; Boston, Massachusetts
Session L08: Superconductivity: Copper Oxide - Methods and Probes |
Hide Abstracts |
Sponsoring Units: DCMP Chair: Timir Datta, University of South Carolina Room: BCEC 150 |
Wednesday, March 6, 2019 11:15AM - 11:27AM |
L08.00001: Circular photogalvanics study of BSCCO high temperature superconductors Se Joon Lim, Martin Greven, Aharon Kapitulnik Recent studies have reported that bulk inversion symmetry may be broken inside the pseudogap region of the phase diagram in YBa2Cu3Oy single crystals. Here, we report signatures of inversion symmetry breaking in another family of cuprate high temperature superconductors, Bi2Sr2CaCu2O8+δ, using circular photogalvanic measurements. |
Wednesday, March 6, 2019 11:27AM - 11:39AM |
L08.00002: Three Laws of Electronic Thermal Conductivity
of High Temperature Superconductors via Dipolon Theory Ram Sharma Recently we predicted [1] a universal peak in electronic thermal conductivity (ETC) of hIgh $T_C$ superconductors (HTSCs) via the dipolon theory [2-5]. Previously the dipolon theory has predicted the two high energy and one low energy kinks besides a new very low energy kink in HTSCs. Here we present the three laws of ETC which explain not only the origin but also the behavior of ETC in HTSCs: First Law: The ETC is due to the rate of increase of the quasiparticle energy distribution (ROIOTQED) with temperature particularly near the Fermi level. Second Law: The ROIOTQED becomes maximum at temperature $T^{(p)}$ given by $\Delta (0) /k_BT^{(p)} = 2.40 $. Third Law: Where there is a superconducting energy gap, there is a peak in the ETC at the temperature $T^{(p)}$. |
Wednesday, March 6, 2019 11:39AM - 11:51AM |
L08.00003: High Pressure 3D to 2D Tuning of Magnetism in Cuprates Markus Huecker, Genda Gu, John Tranquada, Bernd Büchner Broken lattice symmetries often play an integral part in the selection process of the electronic ground state. A prime example is found in the La-214 cuprates, where lattice distortions result in a complex relationship between superconductivity, charge and magnetic orders. In an attempt to dissect this problem into its various parts, here we highlight the impact of lattice distortions on the pristine magnetism of a cuprate parent compound. |
Wednesday, March 6, 2019 11:51AM - 12:03PM |
L08.00004: Uniaxial strain susceptibilities of superconducting Tc and charge order transition temperature from sound velocity measurements in YBCO David LeBoeuf, Siham Benhabib, Mehdi Frachet, francis laliberté, cyril proust, Toshinao Loew, Juan Porras, Mathieu Le Tacon, Bernhard Keimer
|
Wednesday, March 6, 2019 12:03PM - 12:15PM |
L08.00005: Noisy defects in a doped Mott insulator Freek Massee, Yingkai Huang, Mark Golden, Marco Aprili Detailed studies of the effect of single dopant atoms on the local electronic properties are crucial for a full understanding of the macroscopic characteristics of host materials ranging from semiconductors to high temperature superconductors. Due to limited time resolution of conventional scanning tunnelling microscopes, most atomic scale studies of the latter systems focussed on the time averaged effect of dopants on the electronic structure. I will present how, by using atomic scale shot-noise measurements in the high temperature superconductor Bi2Sr2CaCu2O8+x, we visualize sub-nanometre sized objects where remarkable dynamics leads to an enhancement of the tunnelling current noise by at least an order of magnitude. From the position, current and energy dependence we deduce that these defects are oxygen dopant atoms whose local environment leads to charge dynamics that strongly affect the tunnelling mechanism. Possible effects on superconductivity will be discussed. |
Wednesday, March 6, 2019 12:15PM - 12:27PM |
L08.00006: Steady-state superconductivity in electronic materials with repulsive interactions Oliver Hart, Garry Goldstein, Claudio Chamon, Claudio Castelnovo We study the effect of laser driving on a minimal model for a hexagonal two-dimensional material with broken inversion symmetry. Through the application of circularly polarised light and coupling to a thermal free electron bath, the system is driven into a nonequilibrium steady state with asymmetric, nonthermal carrier populations in the two valleys. We show that, in this steady state, interband superconducting correlations between electrons can develop independent of the sign of the electron-electron interactions. We discuss how our results apply, for example, to transition metal dichalcogenides. This work opens the door to technological applications of superconductivity in a range of materials that were hitherto precluded from it. |
Wednesday, March 6, 2019 12:27PM - 12:39PM |
L08.00007: Tuning the Josephson vortex lattice structure with pancake vortices in Bi2Sr2CaCu2O8+δ single crystals Simon Bending, Peter J Curran, Hussen A Mohammed, Alexei E Koshelev, Yuji Tsuchiya, Tsuyoshi Tamegai Vortex structures in the highly anisotropic superconductor Bi2Sr2CaCu2O8+δ depend on the angle the applied field makes with the CuO2 layers; stacks of pancake vortices form when the field is perpendicular to these and highly elliptical Josephson vortices form when it is parallel to them. For tilted magnetic fields, pancake and Josephson vortices coexist and interact in complex ways to form vortex chains and composite vortex lattices, reflecting the delicate balance between attractive and repulsive interactions. Scanning Hall microscopy has been used to map the rich tilted-field vortex phase diagram in an underdoped Bi2Sr2CaCu2O8+δ single crystal. We find that the Josephson vortex lattice spacing has an unexpected non-monotonic dependence on pancake vortex density linked to a field-driven structural transformation with increasing out-of-plane fields. We establish the exact evolution of vortex-chain phases as the out-of-plane field is increased and identify especially stable structures spaced by an integer number of rows of interstitial pancake vortex stacks. Our experimental results are in good semi-quantitative agreement with a theoretical model. |
Wednesday, March 6, 2019 12:39PM - 12:51PM |
L08.00008: Enhancement of critical current density and mechanical properties of BiPb-2223 superconductor phase added with Nano-sized Gd-123 phase Aly Abou-Aly, Nayera Mohammed, mai barakat, Mohammed Hassan, Ramadan Awad Ball milled Nano-sized of Gd-123 superconductor phase was added to the high temperature superconductor (HTSC) BiPb-2223 phase with weight percentage 2.0 wt.%. The milling times t was varied up to 180 min. The samples have a general stoichiometry of (Gd1.0Ba2.0Cu3.0O8+δ)2.0/Bi1.8Pb0.4Sr2.0Ca2.0Cu3.2O10+δ. The samples were prepared by the standard solid-state reaction method. The ball milled superconductor Gd-123 phase was characterized by X-ray powder diffraction (XRD) and transmission electron microscope (TEM) confirming the Nano-scale crystallite size. The prepared samples were characterized by XRD and the scanning electron microscope (SEM). Samples were examined by electrical resistivity and IV measurements in addition to Vickers micro hardness. No significant change in the superconducting transition temperature Tc has been noticed for all samples. The highest relative volume fraction for BiPb-2223 phase was recorded for the sample with t = 120 min. The critical current density Jc was increased from 326, for free sample, up to 1860 A/cm2, for added sample, with grain size 17.52 nm. The micro hardness data was analyzed using several models. The modified proportional sample resistance (MPSR) model is the model that can describe the behavior of our samples successfully. |
Wednesday, March 6, 2019 12:51PM - 1:03PM |
L08.00009: Structural Phase Transitions: a Limiting Factor for Quantum Criticality and Superconductivity in La1.6−xNd0.4SrxCuO4 Qianli Ma, Mirela Dragonmir, James P.I. Clancy, Ashfia Huq, Bruce Gaulin One branch of the La-214 family of cuprate superconductors, La1.6−xNd0.4SrxCuO4, has been of great interest as it displays the full complexity of the canonical hole-doped high TC phase diagram. The strong dependence of the electronic properties on the crystal symmetry has motivated careful diffraction studies of the La1.6−xNd0.4SrxCuO4 structural phase diagram. |
Wednesday, March 6, 2019 1:03PM - 1:15PM |
L08.00010: d-wave Andreev reflection study of the ab-plane proximity effect in cuprate/manganite and cuprate/nickelate thin films Rainni Chen, Chao Zhang, Chris Granstrom, John Y.T. Wei An anomalously long-range proximity effect was previously reported in c-axis thin-film heterostructures of ferromagnetic La2/3Ca1/3MnO3 (LCMO) and superconducting YBa2Cu3O7−δ (YBCO), and attributed to spin-triplet d-wave pairing [1]. However, there is debate over the existence of such long-range proximity effect, given the short c-axis coherence length of YBCO, and since scanning tunneling spectroscopy (STS) on c-axis LCMO/YBCO bilayers has failed to observe any direct evidence [2]. For YBCO/LCMO bilayers oriented along the a-axis, similar STS measurements have reportedly observed a proximity length scale of ~ 30 nm [3]. In this work, we extend these prior STS studies to YBCO/LCMO bilayers oriented along the <110> axis, a geometry that is expected produce the most robust d-wave Andreev resonance states. We also measure <110>-oriented LaNiO3/YBCO bilayers, as a non-magnetic control. Our data are analyzed in terms of the overlayer thickness, in an effort to determine the actual length scale of the manganite/cuprate proximity effect in the ab-plane. |
Wednesday, March 6, 2019 1:15PM - 1:27PM |
L08.00011: Atomically thin high-temperature superconductors Yuying Zhu, Menghan Liao, Jin Zhang, Ruidan Zhong, John Schneeloch, Genda Gu, Kaili Jiang, Ding Zhang, Xucun Ma, Qikun Xue
|
Wednesday, March 6, 2019 1:27PM - 1:39PM |
L08.00012: New Mechanism of Umklapp Scattering in Cuprate High-Tc Superconductors Rong Li, Zhen-Su She Cuprates display several novel symmetry-broken orders such as spin stripe, charge density wave (CDW). We propose a novel mechanism of dissipative umklapp scattering contributing to anomalous transport by fluctuating order beyond fermi surface reconstruction to electronic spectrum. Spatial-temporal fluctuating order is assumed to introduce umklapp scattering of holes, which yields a relaxation time proportional to square of order's periodicity (lo) and a resistivity ρ=h/(π2e2nclo2). This achieves a remarkable link between microscopic fluctuating orders and macroscopic transport, which yields a length mapping method (i.e. lo∝ρ-1/2) to derive orders' periodicity from resistivity data. The theory is validated by data of three classes of samples in LSCO, Bi-2201 and Bi-2212. We show that at underdoped regime at 'knee' temperature (of ρ vs T), lo is indeed close to 2a0, which is the periodicity of antiferromagnetism, while at overdoped regime lo is near 4a0, the CDW periodicity. In a vortex liquid, lo is found to vary as reduced vortex distance (∝B-1/2), and in strange metal as reduced de Broglie wave length (∝T-1/2). These results demonstrate the universal validity of the new umklapp scattering mechanism and the length mapping method, providing a new tool to study order transitions. |
Wednesday, March 6, 2019 1:39PM - 1:51PM |
L08.00013: Reconfigurable SQUID Arrays Sichao Yu, William Andrew Mayer, Matthieu Dartiailh, Kaushini Wickramasinghe, Joseph Yuan, Javad Shabani Superconducting quantum interference devices (SQUID) are widely used for sensitive magnetic field detection. Traditional SQUID arrays based on Superconductor/Insulator junctions have limited flexibility as junction properties are not tunable. The realization of Superconductor/Semiconductor junctions allows for gate-tunable junction properties. This allows for complex tunable SQUID arrays that can be continuously adjusted with voltage gates. We numerically study tunable SQUID arrays with various circuit geometries. Potential applications of these arrays include increased sensitivity to spatial inhomogeneity of fields and variable spatial resolution. Another potential advantage that is numerically explored is leveraging time dependent gate voltages to filter noise and increase sensitivity. |
Wednesday, March 6, 2019 1:51PM - 2:03PM |
L08.00014: Scanning SQUID Microscopy on fractional flux quanta with on-chip field control Pim Reith, Michael Faley, Christoforus Dimas Satrya, Alexander Golubov, Hans Hilgenkamp
|
Wednesday, March 6, 2019 2:03PM - 2:15PM |
L08.00015: Modeling Resonances in the Current-Voltage Characteristics of SQUID Susceptometers Samantha Davis, John Kirtley, Kathryn Ann Moler In Scanning SQUID Microscopy, SQUID susceptometers are tools for achieving extremely precise magnetic imaging and local susceptibility measurements with high spatial resolution. Further development of scanning SQUID microscopy demands a thorough understanding of the properties of SQUID susceptometers. One mysterious behavior is the presence of resonances in the current-voltage characteristics of SQUID susceptometers for scanning applications. The origins and the effects of the resonances on the performance of these SQUIDs is unknown. To illuminate the origin and impact of the resonances, we have developed a model that successfully reproduces the experimentally-determined current-voltage characteristics of SQUIDs for one resonance. We explore the limitations of our model by calculating the noise characteristics of SQUIDs of different designs and comparing the results with experimental noise measurements. Looking forward, we aim to extend the model to encompass all the resonances that appear in experimental data. We will then use the model to optimize the signal-to-noise characteristics of scanning SQUID susceptometers. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700