1. ROLE OF LATTICE VIBRATIONS IN SUPERCONDUCTIVITY
by Art Robinson
(Contacts: alessa@stanford.edu, zxshen@stanford.edu)

The mechanism responsible for high-temperature superconductivity remains elusive. The observation of spectral features occurring at a characteristic energy (an energy scale) often provides significant insight into physical processes in the material. Now, an international collaboration between researchers from Stanford University, the University of Tokyo, and the ALS has evidence from high-resolution angle-resolved photoemission spectroscopy (ARPES) for a common energy scale in three different families of high-temperature superconductors. Several chains of evidence argue that, in contrast to most recent thinking, lattice vibrations must have a role in the superconductivity in these materials.

Read the full story at http://www-als.lbl.gov/als/science/sci_archive/48lattice_vibration.html.

Publication about this research: A. Lanzara, P.V. Bogdanov, X.J. Zhou, S.A. Kellar, D.L. Feng, E.D. Lu, T. Yoshida, H. Eisaki, A. Fujimori, K. Kishio, J.I. Shimoyama, T. Noda, S. Uchida, Z. Hussain, and Z.X. Shen, "Evidence for Ubiquitous Strong Electron-Phonon Coupling in High-Temperature Supereconductors," Nature 412, 510 (2001).

2. SAWATZKY ON SPIN, CHARGE, AND ORBITAL DEGREES OF FREEDOM

Professor George Sawatzky, Canada Research Chair in Condensed Matter Physics at the University of British Columbia (UBC), gave a colloquium at the ALS on October 11. ALS colloquia are given by distinguished scientists who are periodically invited to speak on various subjects of interest to the ALS community. Professor Sawatzky, who recently moved to UBC from the University of Groningen in the Netherlands, is one of Europe's most respected scientists in condensed matter physics and a much-sought-after speaker at international conferences. His work relies on sensitive spectroscopic methods to study electronic structure and motion in nanostructured solids. He has developed a description of the electronic properties of solids that combines the best of quantum chemistry and correlated electron physics. The resulting ideas lead to powerful new techniques for exploring many modern solid-state science issues, including the development of high-temperature superconductors, manganese oxide colossal magnetoresistant (CMR) materials, transition metal compounds, and molecular devices.

In his talk at the ALS, Prof. Sawatzky explored the interplay between spin, charge, and orbital degrees of freedom in strongly correlated systems. Examples of such systems include CMR materials, "frustrated systems" whose structures allow an infinite number of energetically equivalent ordered states, and systems with strange magnetic behavior (e.g., where the magnetic moment finds itself lined up antiparallel to an applied field). Phase diagrams for such systems are very complex, and experiments indicate that, at the phase transitions, a kind of dynamic phase separation occurs in the form of bubbles, stripes, globs, and lines. These phenomena and the time scales of their fluctuations present very interesting open questions in which Prof. Sawatzky believes soft (resonant) x-ray scattering will play an extremely important role. At wavelengths on the order of 10 to 20 angstroms and at resonance, he said, x-ray scattering will be extremely sensitive to spin, charge, orbital, and lattice degrees of freedom. Not only can such experimental techniques help us understand the exotic systems described above, but they can also be used to take a second look at "well understood" systems such as nickel oxide and vanadium trioxide, where surprising new insights into the actual physics behind their properties have already been obtained.

3. DOE'S DECKER DEDICATES SUPERBENDS

James Decker, acting director of the U.S. Department of Energy (DOE) Office of Science, offered his congratulations and thanks to ALS leaders and staff in a small dedication ceremony Thursday, October 4, the first full day of user operations with superbends in the storage ring. Decker commented that the ALS has had a truly admirable record of scientific productivity, and he believes that the superbends will generate a new surge in productivity, particularly in subjects relevant to Office of Science focus areas, such as nanoscience and genomics. The successful incorporation of superbends, he said, has changed the way the world thinks about third-generation light sources. After the remarks, the DOE delegation assembled at Beamline 8.3.1, the first superbend beamline to be completed, to hear beamline spokesperson Tom Alber (Univ. of California, Berkeley) describe some of its features and to get a glimpse of superbend light on a monitor. The visit to the ALS was part of DOE's annual On-Site Review of Berkeley Lab's scientific and operations programs. Also attending were DOE Oakland Operations Office Manager Camille Yuan-Soo Hoo and Berkeley Site Office Manager Dick Nolan.

4. UEC ELECTIONS TO BE CONDUCTED ELECTRONICALLY
(Contact: ALRobinson@lbl.gov)

The election of new members to the ALS Users' Executive Committee (UEC) will be conducted online this year following the conclusion of the annual ALS Users' Meeting this week. The election Web site, which provides details about the election process, can be found at http://www-als.lbl.gov/als/uec/vote/. The following candidates have been nominated to fill three regular seats: Felicia Hendrickson Betancourt (Berkeley Lab), Ali Belkacem (Berkeley Lab), John Bozek (ALS), Michael C. Martin (ALS), Alexander Moewes (Univ. of Saskatchewan), Yasuji Muramatsu (Japan Atomic Energy Research Institute), Ronald A. Phaneuf (Univ. of Nevada, Reno), Z.Q. Qiu (Univ. of California, Berkeley, and Berkeley Lab), Eli Rotenberg (ALS), and Tony van Buuren (Lawrence Livermore National Laboratory). In addition, Alejandro Aguilar (Univ. of Nevada, Reno) and Sophie E. Canton (Western Michigan Univ. and ALS) have been nominated for the student/postdoc seat. Biographical information for each nominee will be posted on the election Web site as soon as it becomes available. The newly elected members will take office on January 1, 2002, and serve on the committee for three years.

5. FIRST CALL: GENERAL SCIENCES PROPOSALS DUE DECEMBER 1
(Contact: alsproposals@lbl.gov)

The User Services Office is now accepting proposals from scientists who wish to conduct research as independent investigators in the general sciences during the running period from June to November 2002. The deadline for submissions is December 1, 2001. (This information does not apply to protein crystallography proposals, which have a separate process and schedule.) Scientists wishing to renew a previous proposal must fill in a one-page Experiment Report/Beamtime Request and submit it to the User Services Office by the December 1 deadline. The numeric rating for each proposal will be communicated to the investigator along with comments from the Proposal Study Panel, where appropriate. The cutoff rating for each beamline in the previous proposal cycle is published on the Web (see below). The following resources are available for further information:

ALS User Services Administrator

alsuser@lbl.gov

Independent investigator process

http://www-als.lbl.gov/als/quickguide/independinvest.html

Beamline information

http://www-als.lbl.gov/als/als_users_bl/datasheets.html

http://www-als.lbl.gov/als/als_users_bl/bl_table.html

Proposal Study Panel (PSP) scores

http://www-als.lbl.gov/als/quickguide/pspscores.html

6. RESULTS OF SECOND POLL ON REFILL TIMES
(Contact: B_Feinberg@lbl.gov)

The results of the second user poll on storage-ring refill times are in. The users showed an overwhelming preference for the eight-hour, fixed-time option (96 votes) compared to the six-hour, variable-time option (35 votes). There was no significant preference regarding the start time (either 7 a.m. or 9 a.m). The ALS operators have suggested a 9 a.m. start time, because it means that refills will generally occur near the beginning of their shifts, when they are fresh.

Accordingly, after going over these results with the Strategic Management Team, we have started the new fiscal year (which begins October 1) using an eight-hour, fixed-time schedule, with refills at 9 a.m., 5 p.m., and 1 a.m.

7. WHO'S IN TOWN: A SAMPLING OF ALS USERS

Following are some of the experimenters who will be collecting data during the next two weeks at the ALS.

Beamline 1.4.3
T.J. Wilkinson (Berkeley Lab)
Harvey Doner (Univ. of California, Berkeley)
Upal Ghosh (Stanford Univ.)
Hoi-Ying Holman (Berkeley Lab)
Felicia Betancourt (Berkeley Lab)

Beamline 4.0.1-2
Jeffrey Kortright (Berkeley Lab)
Boris Sinkovic (Univ. of Connecticut)
George Waddill (Univ. of Missouri-Rolla)

Beamlines 5.0.1, 5.0.2, and 5.0.3
Dong Hae Shin, Jeroen Brandsen, and Ursula Schulze-Gahmen (Berkeley Structural Genomics Center)
Hideaki Shimizu, B. Bhakar, Latesh Lad, Mack Flinspach, and Jonathan Friedman (Univ. of California, Irvine)
Xiaoping Dai and Yu An (The Scripps Research Institute)
Glen Spraggon, Andreas Kreusch, Scott Lesley, and Chris Lee (Novartis Institute for Functional Genomics)
Ray Stevens, Mike Hanson, and Michael Bracey (The Scripps Research Institute)
Duncan McRee (Syrrx, Inc.)
Rune Hartmann (The Cleveland Clinic Foundation)
Clare Peters-Libeu (J. David Gladstone Institutes)
Brian Chapados, Timothy Wood, Li Fan, Gabriel Moncalian (The Scripps Research Institute)

Beamline 6.3.1
Yasuji Muramatsu (Japan Atomic Energy Research Institute)
Hisanobu Wakita (Fukuoka Univ., Japan)
Maurizio Sacchi (Univ. Paris-Sud)

Beamline 7.0.1
Z. Q. Qiu (Univ. of California, Berkeley)
Elaine Seddon (Daresbury Laboratory, UK)
Jinghua Guo (Berkeley Lab)
Joseph Nordgren (Uppsala Univ., Sweden)
Jeffrey Kortright (Berkeley Lab)

Beamline 7.3.3
Ersan Ustundag (California Institute of Technology)

Beamline 8.0.1
Ernst Kurmaev (Russian Academy of Sciences)

Beamline 9.3.2
David Shuh (Berkeley Lab)
Hendrik Bluhm (Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany)

Beamline 10.0.1
Andrew Yencha (State University of New York, Albany)

8. OPERATIONS UPDATE
(Contact: Lampo@lbl.gov)

For the user runs of October 4 - 8 (1.5 GeV) and 9 - 15 (1.9 GeV), the beam reliability (time delivered/time scheduled) was 91%. Of the scheduled beam, 75% was delivered to completion without interruption. There were no significant outages.

Long-term and weekly operations schedules are available on the Web (http://www-als.lbl.gov/als/accelinfo.html). Requests for special operations use of the "scrubbing" shift should be sent to Bruce Samuelson (BCSamuelson@lbl.gov, x4738) by 1:00 p.m. Friday. The Accelerator Status Hotline at (510) 486-6766 (ext. 6766 from Lab phones) features a recorded message giving up-to-date information on the operational status of the accelerator.

LBNL/PUB-848
Editors: lstamura@lbl.gov, alrobinson@lbl.gov, amgreiner@lbl.gov

This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.