Bulletin of the American Physical Society
APS March Meeting 2010
Volume 55, Number 2
Monday–Friday, March 15–19, 2010; Portland, Oregon
Session L40: Superconductivity: Electronic Structure (ARPES) |
Hide Abstracts |
Sponsoring Units: DCMP Chair: Michael Norman, Argonne National Laboratory Room: F151 |
Tuesday, March 16, 2010 2:30PM - 2:42PM |
L40.00001: Momentum and doping dependence of oxygen isotope substitution in cuprates N.C. Plumb, H. Iwasawa, J.F. Douglas, T.J. Reber, K. Sato, H. Eisaki, Y. Yoshida, H. Bando, T. Saitoh, A. Ino, M. Taniguchi, M. Arita, K. Shimada, H. Namatame, T. Masui, S. Tajima, S. Uchida, Y. Aiura, D.S. Dessau We use angle-resolved photoemission spectroscopy at low photon energy to investigate the evolution of the isotope effect in cuprate superconductors as a function of k and doping. When $^{18}$O is substituted for $^{16}$O, the isotope shift in the main kink energy (previously only reported at the superconducting node) is seen to persist away from the node, while the location of the overall kink decreases in energy. ~We perform detailed analysis of the self-energy and isotope effect with the aim of acquiring new insights into how the electron-phonon interactions evolve over the Fermi surface for various dopings. [Preview Abstract] |
Tuesday, March 16, 2010 2:42PM - 2:54PM |
L40.00002: Angle-Resolved photoemission spectroscopy on Tl$_2$Ba$_2$CuO$_{6+\delta}$ G. Levy, M. Raichle, D. Fournier, J. Mottershead, C. Veenstra, J. Rosen, A. Bostwick, E. Rotenberg, R. Liang, W. Hardy, D. Bonn, A. Damascelli Tl2201 is characterized by a simple and undistorted crystal structure, as well as less disorder than other high-T$_c$ cuprate-based materials. On the very overdoped side of the phase diagram, a remarkable agreement has already been achieved between transport (i.e., AMRO and dHvA) and ARPES studies $[1-3]$. We here will present ARPES data on high-quality Tl2201 single crystals and compare them with transport results from the same material across the phase diagram, with emphasis on the evolution of Fermi surface volume, Fermi velocity, and many-body renormalization. We will also discuss the possibility of driving the doping on this material into the underdoped regime by in-situ potassium evaporation.\\[4pt] [1] N. E. Hussey \textit{et al.}, Nature 425, 814 (2003).\\[0pt] [2] M. Plat\'e \textit{et al.}, Phys. Rev. Lett. 95, 077001 (2005).\\[0pt] [3] B. Vignolle \textit{et al.}, Nature 455, 952 (2008). [Preview Abstract] |
Tuesday, March 16, 2010 2:54PM - 3:06PM |
L40.00003: Evidence from Laser ARPES of Electron-Optical Phonon Coupling Near the Node of Optimally Doped Bi2212 Jonathan Rameau, Hongbo Yang, Peter Johnson Laser based photoemission with photons of energy 6 eV is used to examine the fine details of the very low energy electron dispersion and associated dynamics in the nodal region of optimally doped Bi2212. A ``kink'' in the dispersion in the immediate vicinity of the Fermi energy is associated with scattering from an optical phonon previously identified in Raman studies. The identification of this phonon as the appropriate mode is confirmed by comparing the scattering rates observed experimentally with the results of calculated scattering rates based on the properties of the phonon mode as well as the mode's observed dispersion with respect to Fermi surface angle at low temperature. [Preview Abstract] |
Tuesday, March 16, 2010 3:06PM - 3:18PM |
L40.00004: Auto-correlation ARPES study of Pb-Bi2201 Makoto Hashimoto, Ruihua He, Jean-Pierre Testaud, Worawat Meevasana , Rob Moore, Donghui Lu, Yoshiyuki Yoshida, Hiroshi Eisaki, Thomas Devereaux, Zahid Hussain, Zhi-Xun Shen It is important to understand the electronic structure in momentum (k-) and real (r-) spaces in a unified picture. In high-temperature (Tc) cuprates, the different shape of superconducting gap anisotropies have been found by scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES). While the ARPES studies show simple d-wave superconducting gap around the node below Tc, the STM studies which approach superconducting gap anisotropy in k-space by employing the ``octet model'' show the deviation from simple d-wave superconducting gap especially in the underdoped region. To explore this issue, we study auto-correlation (AC-) ARPES spectra of optimally doped Pb-Bi2201 measured at T $<<$ Tc, Tc $<$ T $<<$ T*, and T $>$ T*. The obtained AC-ARPES spectra show very similar behavior to the reported Fourier transformed STM spectra. In the presentation, we will compare these ARPES and STM results and discuss the relationship between r- and k-space focusing on the superconducting gap anisotropy. [Preview Abstract] |
Tuesday, March 16, 2010 3:18PM - 3:30PM |
L40.00005: High energy scales in e-doped HTSCs observed with ARPES F. Schmitt, B. Moritz, S. Johnston, E. M. Motoyama, M. Greven, D. H. Lu, R. G. Moore, T. P. Devereaux, Z.-X. Shen, R. T. Scalettar The rich physics observed in the high temperature superconducting cuprates (HTSCs) arises from many interactions at different energy scales. While some interactions involving higher energy scales are captured by Mott physics, some of the lower energy pehenomena are captured better with more itinerant, mean-field type models. Since these different energy scales affect each other, it is challenging to assign origins to quasiparticle renormalizations observed by angle-resolved photoemission spectroscopy (ARPES). One of these features observed by ARPES, which involves a vertical drop in the band dispersion in the h-doped HTSCs at around 0.3eV, is usually termed high energy anomaly (HEA). We present new ARPES data on an e-doped HTSC, showing a similar HEA and will discuss its possible origin with the help of simulations of a single-band Mott-Hubbard model. Other experimental results also will be discussed. [Preview Abstract] |
Tuesday, March 16, 2010 3:30PM - 3:42PM |
L40.00006: Investigation of charge order in Ca$_{2-x}$Na$_{x}$CuO$_{2}$Cl$_{2}$ using ARPES Jianqiao Meng, M. Brunner, Gey-Hong Gweon, K.-H. Kim, H.-G. Lee, S.-I. Lee The electronic structure of doped cuprate superconductors Ca2-xNaxCuO2Cl2 of various doping values (including underdoping, optimal doping and overdoping) is investigated using angle-resolved photoemission spectroscopy (ARPES). We discuss our new data in terms of charge order, by comparing them with the ARPES data and the scanning tunneling spectroscopy data in the literature. [Preview Abstract] |
Tuesday, March 16, 2010 3:42PM - 3:54PM |
L40.00007: IR and dc magneto-transport and ARPES compared: n-type cuprates H.D. Drew, G.S. Jenkins, D.C. Schmadel, P.L. Bach, R. Greene, H. Kontani, X. B\'echamp-Lagani\`{e}re, G. Roberge, P. Fournier IR Hall angle measurements were performed on under- and overdoped $Pr_{2-x}Ce_{x}CuO_{4}$ (PCCO) samples at sufficiently low optical excitation energies (below 10meV) to directly probe the Fermi-surface (FS) properties. In the underdoped samples, a rapid reduction of the Hall mass with decreasing doping indicating formation of FS pockets will be discussed in terms of ARPES measured arcs. In the overdoped samples, the low temperature finite-frequency Hall coefficient $R_H$ is severely suppressed below the low temperature dc $R_H$ as well as the value predicted by ARPES data analyzed within the relaxation time approximation. This suppression with frequency is similar to the dc suppression observed at temperature T$\sim \omega$. The addition of electronlike contributions to the ac $\sigma_{xy}$, even at T=0, directly implicates inelastic scattering as the causal mechanism of the anomalous Hall effect in PCCO. These results will be discussed in terms of Fermi liquid theories utilizing the ARPES measured Fermi surfaces. [Preview Abstract] |
Tuesday, March 16, 2010 3:54PM - 4:06PM |
L40.00008: Probing the symmetry of the pseudogap in cuprates superconductors with Angular Resolved Photoemission Spectroscopy (ARPES) Ari D. Palczewski, Takeshi Kondo, Adam Kaminski, J.S. Wen, G.Z.J. Xu, G. Gu There is still no consensus on the origins of the pseudogap in cuprate superconductors; recent studies have shown that it is probably not a preformed cooper pair state, but a completely different state that competes with superconductivity. Some of the possible different states include a charge density state where electrons scatter between a Q-vector connecting the nested bands close to ($\pi $,0) or a spin density state that is derived from the ($\pi $,$\pi )$ Q-vector. The difference between the two, or other exotic states, might be ascertained by looking at the symmetry of the pseudogap as a function of momentum space. We use Angular Resolved Photoemission Spectroscopy (ARPES) to probe this symmetry or lack thereof in cuprates. [Preview Abstract] |
Tuesday, March 16, 2010 4:06PM - 4:18PM |
L40.00009: ARPES study of the YBCO phase diagram by in-situ K evaporation D. Fournier, G. Levy, J.L. McCheyney, A. Bostwick, E. Rotenberg, W.N. Hardy, R.X. Liang, D.A. Bonn, I.S. Elfimov, A. Damascelli The study of the YBCO phase diagram by ARPES has become of central interest since the observation of quantum oscillations in high-magnetic field $[1]$. However, until recently accessing the various electronic phases by photoemission has been hampered by the so-called polar catastrophe $[2]$. In this work, the overdoped metal (OD, p=0.37, T$_c$=0), the superconducting phase (OP, T$<$T$_c$), and the normal state of the pseudogap regime (UD, T$_c<$T $<$T$^*$) have been successfully explored by surface doping (i.e., in-situ K evaporation). This reveals that the dispersion, as well as the arc topology of the low energy excitations of the normal state, are universal $[3]$. While no traces of an electronic reconstruction have been observed in YBCO, we are able to identify the doping value at which the Luttinger description breaks down upon underdoping.\\ \\ $[1]$ N. Doiron-Leyraud \textit{et al.}, Nature 447, 565 (2007).\\ $[2]$ M. A. Hossain \textit{et al.}, Nat. Phys. 4, 527 (2008).\\ $[3]$ K. M. Shen \textit{et al.}, Science 307, 901 (2005). [Preview Abstract] |
Tuesday, March 16, 2010 4:18PM - 4:30PM |
L40.00010: ARPES line shapes of two leg ladder compounds Sr$_{14-x}$Ca$_x$Cu$_{24}$O$_{41}$ Gey-Hong Gweon, Takao Sasagawa, Brandon McGuire, Jianqiao Meng, Matthew Brunner, Jacob Stanley, James Hinton Two leg ladder compounds, Sr$_{14-x}$Ca$_x$Cu$_{24}$O$_{41}$, are quasi-one-dimensional cuprate materials, and provide a reference for considering many interesting and controversial general issues such as non-Fermi liquid, Fermi surface reconstruction, and charge order on a more solid ground. Here we discuss how the line shapes observed for two leg ladder compounds in angle resolved photo- electron spectroscopy (ARPES) may shed light on continuing issues in physics of quasi-two-dimensional cuprates. [Preview Abstract] |
Tuesday, March 16, 2010 4:30PM - 4:42PM |
L40.00011: Towards a more complex superconducting state of cuprates Ruihua He, Makoto Hashimoto, J.P. Testaud, H. Yao, K. Tanaka, W. Meevasana, R.G. Moore, D.H. Lu, Y. Yoshida, M. Ishikado, H. Eisaki, T.P. Devereaux, S.A. Kivelson, Z. Hussain, Z.-X. Shen Compared with the mysterious normal (pseudogap) state of high-Tc superconductivity, the superconducting state itself is generally deemed much better understood. Being most relevant and intensively characterized in momentum-space, its lowest-lying excitations are conceived to concentrate on and exhibit d-wave-like Bogoliubov dispersions along the entire underlying Fermi surface. By using angle-resolved photoemission spectroscopy, here we unveil an elevated complexity of the superconducting state of Bi2201 beyond this picture, which points to a highly non-trivial interplay between coherent superconductivity and coexisting pseudogap of distinct symmetry. We show simulations which assume simple density-wave nature of the pseudogap provide a good starting point to understand this more complex superconducting state. [Preview Abstract] |
Tuesday, March 16, 2010 4:42PM - 4:54PM |
L40.00012: Doping-dependent laser-ARPES studies on Bi-2212 I. M. Vishik, W.-S. Lee, F. Schmitt, B. Moritz, T. Sasagawa, S. Uchida, K. Fujita, S. Ishida, C. Zhang, T. P. Devereaux, Z.-X. Shen With the improved resolution of laser-based ARPES, we can access finer features in the single particle spectrum. We report on our laser-ARPES experiments on Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$ (Bi-2212), particularly on the recently-discovered nodal kink at low energies ($\omega <$10 meV). We have studied the doping dependence of this low-energy kink in the underdoped regime, and we find that the kink is robust for different dopings, with signatures both in the real and imaginary part of the self energy. Moreover, the renormalization of the nodal velocity becomes stronger with underdoping, leading to a doping-dependent nodal Fermi velocity, in contrast to previously reported phenomenology. Together with laser-ARPES measurements of the gap velocity, v$_{2}$, comparisons can be made to thermodynamic measurements. [Preview Abstract] |
Tuesday, March 16, 2010 4:54PM - 5:06PM |
L40.00013: Momentum Dependence of Fluctuation Spectrum of Slightly Underdoped Bi2212 from High Resolution Laser ARPES Jin Mo Bok, Jae Hyun Yun, Han-Yong Choi, Wentao Zhang, X.J. Zhou, Chandra Varma The Eliashberg function describes the spectral function of the fluctuation and their coupling to electrons and is therefore of fundamental importance in determining the normal state properties and pairing mechanism in metals. For conventional superconductors it was successfully extracted by the McMillan-Rowell procedure. For the cuprates, however, its momentum dependence has not yet been determined directly from experimental data. Here, we report the deduction of momentum dependence of Eliashberg function $\alpha ^2F(\theta ,\omega )$ at energy $\omega $ and along momentum cuts at angles $\theta $ normal to the Fermi surface from the high resolution laser angle resolved photoemission spectroscopy on slightly underdoped Bi2212 in normal state. Our principle result is that despite the $\theta $ dependence of the single-particle self-energy, the $\alpha ^2F(\theta ,\omega )$ collapse onto a single function of $\omega $ independent of $\theta $. It has a weak peak around 0.05 eV and an intrinsic cut-off of about 0.4 eV or the energy of the band bottom in direction $\theta $, whichever is lower. These results are consistent only with fluctuation spectra which have the correlation length of the lattice constant or shorter. [Preview Abstract] |
Tuesday, March 16, 2010 5:06PM - 5:18PM |
L40.00014: ARPES study of the Fermi Surface in the Underdoped Bi2212 Hongbo Yang, Jonathan Rameau, Zhihui Pan, Genda Gu, David Hinks, Peter Johnson We examine the structure and temperature dependence of the Fermi surface for an underdoped T$_{c}$ = 45 K sample and compare it with the T$_{c}$ = 65 K sample studied elsewhere. We find, that these materials show little temperature dependence in the Fermi arc length and further find that the ``Fermi pocket'' partially enclosed by the arc appears to scale with the doping level. [Preview Abstract] |
Tuesday, March 16, 2010 5:18PM - 5:30PM |
L40.00015: Extracting Momentum Resolved Tunneling Curves of Bi2212 from ARPES T. J. Reber, N. C. Plumb, Z. Sun, Q. Wang, Y. Aiura, K. Oka, H. Eisaki, M. Hermele, D. S. Dessau Taking advantage of the excellent resolution of low energy ARPES, we can resolve the thermally populated excited states above the Fermi energy near the node of Bi2212, even at quite low temperatures. By integrating the Momentum Distribution Curves (MDCs) and dividing out by the Fermi function, we extract what are essentially momentum-resolved tunneling curves, i.e. curves which vary as a function of location along the Fermi surface. We analyze the scattering rates using a Dynes-style formula and compare these results with what is found from a direct analysis of MDC and EDC widths. Temperature and angular dependences will also be discussed in detail. [Preview Abstract] |
Tuesday, March 16, 2010 5:30PM - 5:42PM |
L40.00016: Detecting Spin Currents in Superconductors by Doppler-shifted Spin-polarized Photoemission Aris Alexandradinata, J.E. Hirsch A method is proposed to detect high-velocity spin currents by exploiting the Doppler effect to energetically separate photoelectrons of opposite spin polarizations. We predict that a highly polarized photocurrent will emit from the edge of the valence band. For spin currents that are predicted to exist in superconductors by the Spin Meissner effect, the expected Doppler-induced energy separation is measurable with current experimental resolutions. [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