Bulletin of the American Physical Society
APS March Meeting 2015
Volume 60, Number 1
Monday–Friday, March 2–6, 2015; San Antonio, Texas
Session D9: Superconductivity in Cuprates: Photoemission |
Hide Abstracts |
Sponsoring Units: DCMP Chair: Donghui Lu, Stanford University Room: 006D |
Monday, March 2, 2015 2:30PM - 2:42PM |
D9.00001: An Angle Resolved Thermodynamics Study of Cuprate Superconductors Xiaoqing Zhou, Haoxiang Li, Stephen Parham, Justin Waugh, John Schneeloch, Ruidan Zhong, Genda Gu, Helmuth Berger, Kunihiko Oka, Hiroshi Eiaski, Gerald Arnold, Daniel Dessau The thermodynamics properties of a system contain vital information on its electronic states, the contribution of which in typical bulk measurements is averaged and integrated over momentum and energy space, and needs to be carefully isolated from other contributions such as that of phonons. In this work, we demonstrate that the distribution of electronic entropy over momentum and energy space can be directly probed using Angle Resolved Photoemission Spectroscopy, establishing photoemission as an alternative and complimentary probe of electronic thermodynamics. With a series of BSCCO samples that spans the cuprate phase diagram, we investigate their entropy evolution as a function of doping, momentum, energy and temperature, and explore their implications in regards to the nature of the pseudogap phase and possible Fermi surface reconstruction scenarios. [Preview Abstract] |
Monday, March 2, 2015 2:42PM - 2:54PM |
D9.00002: Extraction of normal and pairing self-energies and Eliashberg functions of high temperature superconductor Bi2212 from Laser-based ARPES experiment Jin Mo Bok, Seung Hwan Hong, Jong Ju Bae, Han-Yong Choi, Chandra M. Varma, Wentao Zhang, Junfeng He, Yuxiao Zhang, Li Yu, X.J. Zhou The angle-resolved photoemission (ARPES) measurements provide momentum and frequency dependence of the electronic structure that enables quantitative analysis using single particle Green's function. This is particularly important for studying the cuprate superconductors that are known to have anisotropic electronic structure and anisotropic d-wave superconducting gap. Here we report the extraction of the normal and pairing self-energies from high resolution Laser-based ARPES data of the underdoped and overdoped Bi2212. We also obtain the Eliashberg functions, ${\cal E}_{\mathrm{N}}$ and ${\cal E}_{\mathrm{P}}$, by inverting Eliashberg equations using maximum entropy method. Implications of these results for understanding the superconductivity mechanism will be discussed. [Preview Abstract] |
Monday, March 2, 2015 2:54PM - 3:06PM |
D9.00003: ARPES sensitivity to short-range antiferromagnetic correlations Amit Kanigel, Robert Wallauer, Samuele Sanna, Elias Lahoud, Pietro Carretta We chose Sr$_2$CuO$_2$Cl$_2$, a prototype of a spin $S=1/2$ antiferromagnet (AF) on a square lattice, as a test case for the sensitivity of angle-resolved photoemission spectroscopy (ARPES) to short-range correlations. As expected, in the antiferromagnetic (AF) phase we observe the maximum of the highest occupied band at the ($q_x=\pi/2,q_y=\pi/2$)-point with significant spectral weight beyond the AF zone boundary. At temperatures about twice the N\'eel temperature, owing to the significant AF correlations, almost no change in the spectrum is observed. In order to reduce the correlation length we substituted Cu$^{2+}$ (S=1/2) by Zn$^{2+}$ ($S=0$). The modification of the AF correlation length as a function of Zn concentration and temperature was derived using NMR and a direct correspondence between the amplitude of the spectral weight beyond the AF zone boundary and the correlation length was established. Remarkably, even at correlation lengths as short as 3 lattice constants we still observe a significant spectral weight in the back-bended band. These findings prove that the ARPES technique is very sensitive to short-range correlations and provide a hint for the understanding of ARPES results in the underdoped regime of high temperature superconductors. [Preview Abstract] |
Monday, March 2, 2015 3:06PM - 3:18PM |
D9.00004: Linking dynamic and thermodynamic properties of cuprates: An angle-resolved photoemission study of (Ca$_{x}$La$_{1-x}$)(Ba$_{1.75-x}$La$_{0.25+x}$)Cu$_3$O$_y$ ($x$=0.1 and 0.4 Gil Drachuck, Elia Razzoli, Rinat Ofer, Galina Bazalitsky, R.S. Dhaka, Amit Kanigel, Ming Shi, Amit Keren We report angle-resolved photoemission spectroscopy (ARPES) on two families of high temperature superconductors (Ca$_{x}$La$_{1-x}$)(Ba$_{1.75-x}$ La $ _{0.25+x}$)Cu$_{3}$O$_{y}$ with $x=0.1$ ($T_{c}^{max}=56$ K) and $x=0.4$ ($ T_{c}^{max}=82$ K). The Fermi surface (FS) is found to be independent of $x$ or $y$, and its size indicates extreme sample-surface overdoping. This universal FS allowes the comparison of dynamical properties between superconductors of similar structure and identical doping, but different $ T_{c}^{max}$. We find that the high-energy ($\left\vert E\right\vert >50$ meV) nodal velocity in the $x=0.4$ family is higher than in the $x=0.1$ family. The implied correlation between $T_{c}^{max}$ and the hopping rate $ t $ supports the notion of kinetic energy driven superconductivity in the cuprates. We also find that the antinodal gap is higher for the $x=0.4$ family. [Preview Abstract] |
Monday, March 2, 2015 3:18PM - 3:30PM |
D9.00005: Distinguishing Single-Particle Lifetime and Population Lifetime in a Cuprate Superconductor Shuolong Yang, Jonathan Sobota, Dominik Leuenberger, Yu He, Makoto Hashimoto, Donghui Lu, Hiroshi Eisaki, Patrick Kirchmann, Zhi-Xun Shen We employ femtosecond time- and angle-resolved photoelectron spectroscopy to study optimally doped Bi-2212 (T$_{c} = $ 96 K). In the low excitation limit, the energy-resolved population lifetime displays abrupt changes near 60-80 meV both below and above T$_{c}$. Moreover, the lifetime near this characteristic energy is independent of excitation density. These behaviors are consistent with theories based on electron-boson interactions, which connect the population lifetimes to the single-particle lifetimes measured by equilibrium photoemission. However, the absolute values of these two quantities are different by one to two orders of magnitude. We further demonstrate that this discrepancy is independent of experimental techniques and materials, and point out the fundamental conceptual differences between the two lifetimes. [Preview Abstract] |
Monday, March 2, 2015 3:30PM - 3:42PM |
D9.00006: Temperature Evolution of the Pseudogap and Superconducting Gap in Bi2Sr2CaCu2O8 Superconductor Studied by High Resolution Time-of-Flight Laser-ARPES Yuxiao Zhang, Xingjiang Zhou The relationship between the pseudogap and superconducting gap in high temperature cuprate superconductors remains an outstanding issue. In this talk, we will present our high resolution laser-ARPES measurement on Bi2Sr2CaCu2O8 superconductor. We will use the latest generation of ARPES system equipped with the VUV laser and the time-of-flight (TOF) electron energy analyzer. This enables us to have super-high energy resolution, high momentum resolution, simultaneous coverage of two-dimensional momentum space, high data acquisition efficiency and much reduced nonlinearity effect. From detailed temperature dependence near the nodal and antinodal regions, we will discuss on the relationship between the pseudogap and superconducting gap in the cuprate superconductors. [Preview Abstract] |
Monday, March 2, 2015 3:42PM - 3:54PM |
D9.00007: Phenomenological study of the normal state angle resolved photoelectron spectroscopy line shapes of high temperature superconducting cuprates Kazue Matsuyama, Rohit Dilip, G.-H. Gweon Understanding the normal state properties of high temperature (high-$T_c$) superconducting cuprates remains a central mystery in the high-$T_c$ problem. Standing out among those mysterious properties are the anomalous angle resolved photoelectron spectroscopy (ARPES) line shapes. The extremely correlated Fermi liquid (ECFL) theory recently introduced by Shastry has renewed interest in quantitatively understanding ARPES line shapes. In this talk, we combine certain phenomenological considerations with the ECFL framework in order to describe the ARPES data. Our phenomenological models have the property of preserving the universal property of the original ECFL theory, while introducing phenomenological changes in a non-universal property. Our models describe, with unprecedented fidelity, the key aspects of the dichotomy between momentum distribution curves (MDCs) and energy distribution curves (EDCs) of high-$T_c$ ARPES data. Therefore, our study goes well beyond the prevailing studies that discuss only MDCs and EDCs. [Preview Abstract] |
Monday, March 2, 2015 3:54PM - 4:06PM |
D9.00008: Shift in Chemical Potential of Superconducting Bi2212 Measured by Ultrafast Photoemission Spectroscopy Tristan Miller, Chris Smallwood, Wentao Zhang, Hiroshi Eisaki, Dung-Hai Lee, Alessandra Lanzara Time- and Angle-resolved photoemission spectroscopy (tr-ARPES) has been used to directly measure the dynamics of many different properties of high-temperature superconductors, including the quasiparticle relaxation, cooper pair recombination, and many-body interactions. There have also been several intriguing results on several materials showing how laser pulses can manipulate their chemical potential on ultrafast timescales, and it's been suggested that these effects could find applications in optoelectronic devices. Studies on GaAs have also found that laser pulses may induce a surface voltage effect. Here, we extend these studies for the first time to a Bi2212 sample in the superconducting state, and disentangle the shift in chemical potential from surface voltage effects. [Preview Abstract] |
Monday, March 2, 2015 4:06PM - 4:18PM |
D9.00009: Exploring momentum, temperature and doping dependence of mass renormalization in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ H.X. Li, X.Q. Zhou, S. Parham, T.J. Reber, Y. Cao, J.A. Waugh, Z. Xu, J. Schneeloch, R.D. Zhong, G. Gu, H. Berger, G. Arnold, D.S. Dessau Among the many novel aspects of cuprate high-temperature superconductors, one of the most important is that the parent undoped state of these materials is a strongly correlated Mott insulator. How these correlations impact or contribute to the superconducting state in the doped materials remains a critical aspect of understanding the mechanism of high temperature superconductivity. From a newly developed technique of studying self-energy in Angle-Resolved Photoemission Spectroscopy (ARPES), we explore the mass enhancement at low frequency as a function of momentum, temperature and doping. Comparing our result to the other measures such as specific heat and quantum oscillation, we show that ARPES can be a highly useful tool for effective mass measurement. [Preview Abstract] |
Monday, March 2, 2015 4:18PM - 4:30PM |
D9.00010: trARPES on Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8}$ using Mid-Infrared Pump Stephen Parham, Haoxiang Li, Xiaoqing Zhou, Justin Waugh, Tom Nummy, Justin Griffith, Zhijun Xu, John Schneeloch, Ruidan Zhong, Genda Gu, Daniel Dessau The field of time-resolved ARPES (trARPES) has matured greatly in the last several years and has proven a useful tool in the study of cuprate superconductivity. However, previous experiments have been limited in the pump wavelength to energies of 1.5 eV (or more), far above the relevant energy scales for superconductivity. Here we use an OPA/DFG setup to create a mid-infrared pump, with tunable photon energies from 60-300 meV, allowing us to weakly perturb the superconductivity of optimally doped Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8}$. Here we report on the k-resolved electron and gap dynamics of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8}$ under this excitation scheme. [Preview Abstract] |
Monday, March 2, 2015 4:30PM - 4:42PM |
D9.00011: Can La2CuO4 be made into an undoped metal / superconductor: insights from angle-resolved photoemission Haofei Wei, Carolina Adamo, Darrell Schlom, Kyle Shen La$_2$CuO$_4$ is a well-known parent compound for the hole-doped cuprate superconductors. However, by shiftings the apical oxygen away from the Cu-O plane, it can also be made into the parent for an electron-doped superconductor. La$_2$CuO$_4$ in this so-called T$'$ structure is metastable in bulk, but recent reports have succeeded in stabilizing thin films via molecular-beam epitaxy. These samples were reported to be metallic and even superconducting, in contrast to the Mott insulating state found in all other undoped cuprate parent compounds. To determine whether it is truly a metal in its undoped state, we have for the first time directly measured the electronic structure of epitaxially grown thin films of nominally undoped T$'$-La$_2$CuO$_4$ using in-situ angle-resolved photoemission spectroscopy (ARPES). We observe dispersive bands which form a well-defined Fermi surface with intensity modulations consistent with scattering from an underlying SDW order, similar to those observed in doped n-type cuprates. We have also characterized the carrier density using Luttinger's rule, and will discuss what information our measurements provide on the role of oxygen non-stoichiometry in determining the properties of this system and on the potential for a metallic undoped cuprate. [Preview Abstract] |
Monday, March 2, 2015 4:42PM - 4:54PM |
D9.00012: Photodoping of Effects in Heavily Underdoped Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$ Revealed by Time and Angle Resolved Photoemission Spectroscopy J.D. Rameau, S. Freutel, L. Rettig, Isabella Avigo, M. Ligges, Y. Yoshida, H. Eisaki, J. Schneeloch, R.D. Zhong, X.J. Xu, G.D. Gu, P.D. Johnson, Uwe Bovensiepen While in the last several years great strides have been made in the use of ultrafast optical excitation to induce non-equilibrium effects in the superconducting state of cuprate high Tc superconductors, less attention has been paid to what such pump-probe experiments might reveal about the equilibrium properties of these materials, particularly in their normal states. Recently we have investigated the non-equilibrium properties of the normal state of optimally doped (T$_{c}$ = 91 K) Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$ (Bi2212) using time and angle resolved photoelectron spectroscopy (trARPES). This effort revealed a pump-induced modification of the nodal mass renormalization at 70 meV as well as a longer-lived photodoping effect. Building on this work, we will present further findings related to the photodoping effect as it is manifested in the normal state of heavily underdoped (T$_{c}$ = 50 K) Bi2212. [Preview Abstract] |
Monday, March 2, 2015 4:54PM - 5:06PM |
D9.00013: Analyzing of Superconductivity from Fitting Result of the Diverging Effective Mass in YaBa$_{2}$Cu$_{3}$O$_{6+x}$ Hyun-Tak Kim For cuprate superconductors, the mechanism of high-$T_{c}$ superconductivity is still an unclear and unsolved problem, because they are inhomogeneous. Here, we show analysis of superconductivity from the fitting result of the diverging-effective mass (DEM) extracted from the quantum-oscillation data in YaBa$_{2}$Cu$_{3}$O$_{6+x}$ [1]. The fitting was performed by extended Brinkman-Rice picture [2]. The fitting result presents the Fermi arc observed by angle-resolved-photoemission-spectroscopy data is presented. In particular, the growing Fermi arc from the nodal Fermi point to the isotropic Fermi surface with increasing $x$ and the nodal constant Fermi energy are revealed. Further, pairing symmetry of cuprate superconductors is analyzed as $s$-wave. The quantum critical point is regarded as the nodal Fermi point. The intrinsic superconducting gap is formed at node. The mass divergence is an average effect and the true effective mass is constant.\\[4pt] [1] PNAS 107 (2010) 6179.\\[0pt] [2] Physica C 341-348(2000)259; e-print arXiv:cond-mat/0110112; Physica C 460--462, 1076 (2007). [Preview Abstract] |
Monday, March 2, 2015 5:06PM - 5:18PM |
D9.00014: Ultrafast Quasiparticle Relaxation Dynamics across the Superconducting Vaporization Threshold in Bi2212 Christopher Smallwood, Wentao Zhang, Tristan Miller, Greg Affeldt, Koshi Kurashima, Chris Jozwiak, Takashi Noji, Yoji Koike, Hiroshi Eisaki, Dung-Hai Lee, Alessandra Lanzara In cuprate superconductors, an important open question is the degree to which the timescales and pathways for quasiparticle relaxation relate to underlying mechanisms governing superconductivity, antiferromagnetism, charge ordering, and other types of competing orders. Time- and angle-resolved photoemission spectroscopy (time-resolved ARPES) is uniquely poised to address this question because of the technique's exceptional ability to simultaneously probe the time-, energy-, and momentum-dependent properties of quasiparticles and band structure. Previous time-resolved ARPES studies have examined quasiparticle dynamics in the very high and very low pump fluence regimes, but a systematic study of the changes in dynamics across the fluence vaporization threshold for superconductivity has not yet been undertaken. Here we report the results of studying this regime. [Preview Abstract] |
Monday, March 2, 2015 5:18PM - 5:30PM |
D9.00015: Dipolon Theory of High $T_C$ Superconductivity--First Discovered Two High Energy Kink Features in Electron Energy Ram Sharma It has been revealed that the two high energy kinks in high $T_C$ superconductors (HTSC) in electron energy at $\sim 100 \ mev $ and $\sim 160 \ mev $ which were stated as found new [1], were discovered earlier [2] via dipolon theory [3,4] in explaining the photoemission line shape (sharp peak, dip and broad peak) and the low energy kink at $\sim 70 \ mev $. It was also mentioned [2] that the details for the high energy kinks would be reported elsewhere [5]. Thus Ref. 1 should be corrected by replacing ``new'' by ``discovered earlier'' in the text including the title. The dipolon theory is strong coupling field-theory including Mott renormalization, nonrigid electron bands, electron-hole asymmetry and all important and necessary electron correlations and not only explains but also predicts correctly the properties of HTSC [2-5].\\[4pt] [1] W. Zhang et al., Phys. Rev. Lett. {\bf 100}, 107002 (2008).\\[0pt] [2] R. R. Sharma, Physica {\bf C 468}, 190 (2008); received by the journal on 15 August, 2007; available online 28 November, 2007.\\[0pt] [3] R. R. Sharma, Phy. Rev. {\bf B 63}, 054506 (2001).\\[0pt] [4] R. R. Sharma, Physica {\bf C 439}, 47 (2006).\\[0pt] [5] R. R. Sharma, ``Dipolon Theory of Kink...'', in ``Superconducting...'', Ed. K. N. Courtlandt, P. 81-100, Nova Sc, Pub., Inc., New York, 2009. [Preview Abstract] |
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