Electronic Nematicity without Magnetism in FeSe –
Contact: Donghui Lu, SSRL
In superconducting materials, electron clouds can align into a specific
order termed nematicity, a word taken from a root meaning string-like and
previously used for alignment of molecules in liquid crystal displays (LCDs).
Most iron-based high-temperature superconductors (FeSCs) exhibit nematic order
and magnetic order in conjunction with superconducting behavior. Iron selenide
(FeSe) is a type of FeSC material that obtains nematic but not magnetic
alignment prior to reaching the superconducting state. This provides an
excellent opportunity to disentangle the contribution of these two orders that
usually emerge simultaneously. Studies of FeSe have faced the challenge that
FeSe crystals break into orthogonally-oriented domains at the onset of nematic
order, a process called twinning. A team of researchers has found a way to
detwin FeSe crystals to examine the nematic state to gain a deeper
understanding of how it affects superconductivity. Read more...
New Facilities Coming Soon
Beam Line Developments
This is an exciting time with new beam lines under development at SSRL. We
know that the experimental floor is a busy place and that people are curious
about the new beam line construction, but we remind everyone to exercise
caution in construction areas, particularly between BL15 and BL11-3. As the
beam lines become operational, we will provide detailed information. Beam line map
Advanced Spectroscopy Capabilities to Move from BL6-2b to
BL15-2. Commissioning for our new advanced spectroscopy
undulator beam line, 15-2, is underway. During the transition, some XES/XRS
equipment will be moved from BL6-2 to BL15-2. The beam line will provide
new capabilities for time-resolved studies.
Materials Scattering Capabilities to Move from BL7-2 to
BL17-2. A new undulator beam line is in construction for the
materials scattering community. BL17-2 will add new capabilities in the form of
a micro-focused beam, with high flux. The end station will be capable of
performing simultaneous SAXS/WAXS measurements, as well as experiments which
require the 6-circle diffractometer which will move from 7-2. The work on
the beam line is progressing rapidly. The hutch, optics, and beam
transport systems have been installed. First light to the monochrometer
slits was achieved Tuesday the 27th of January. We look
forward to running commissioning experiments at the end of cycle 3 for this
run. BL7-2 will no longer be available for user experiments after February 2020
when equipment will be moved from that line for installation on BL17-2.
Microfocus Macromolecular Crystallography BL12-1 in
Commissioning. This is SSRL’s second microbeam undulator
beam line for structural biology, funded as a PRT with Stanford and The Scripps
Research Institute as partners. BL12-1 will feature a pixel array
detector (Eiger X 16M), a flexible monochromator with rapid switching between
crystals or multilayers, and a high-speed micro-goniometer. It will
support a range of sample environments (cryogenic to room temperature with
humidity control) and sample delivery systems, including injectors and
Soft X-ray Metrology Capabilities on BL16-2.
Commissioning is underway on BL16-2, a soft x-ray beam line dedicated for the
characterization of x-ray detectors, x-ray optics and dispersive
components. BL16-2 is equipped with a theta/2 theta system, motorized
x,y,z motion sample adjustment with manual tilt adjustment, two in-vacuum JJ
slit assemblies, 3 different detectors (IRD silicon photodiode, windowless
Amptec SDD, and a Amptec SDD with a 0.3 micron Be window).
See SSRL beam line techniques and parameters
Request for Publications Related to SSRL Beam Time
SSRL provides technical tools for user experiments with the requirement that
scientists will report and properly acknowledge use of our facility and funding
agencies in resulting publications. Acknowledgement templates are provided on our website.
With a DOE triennial review coming up in the spring it will be important to
have up-to-date records of 2017-2019 publications related to work done at SSRL.
Please take a few minutes to review our publications database to confirm that your most recent
SSRL-related publications are included, and please enter the information on any
that are missing.
Stanford-SLAC Cryo-EM Center Beginning Practical Workshop, Mar
The Stanford-SLAC Cryo-EM Center (S2C2) will offer a
beginning cryo-EM training workshop March 23–25, 2020. Onsite attendance
for the lecture sessions is limited to ~40 participants with additional access
provided via Zoom teleconferencing. The hands-on sessions are limited to 12
participants. There is no fee for this workshop. The first round of
notifications for onsite participation in the hands-on sessions will be sent
out on February 15. Registration will remain open until March 15 for
onsite lecture sessions only and remote participation. Workshop Website
RapiData 2020 at SSRL is a practical course in macromolecular x-ray
diffraction data collection, data processing and structure solution. The aim of
the RapiData course is to educate and train young scientists in data collection
and processing methods at synchrotron beamlines, using state-of-the-art
software and instrumentation. RapiData 2020 Website
Cryo-EM Image Processing Workshop, Jun 8–10, 2020 — Save
U.S. Particle Accelerator School Summer 2020 Session
78th Annual Pittsburgh Diffraction Society Conference, Menlo Park,
CA, Sep 27–29, 2020
SSRL/LCLS Users' Meeting and Workshops, Sep 30–Oct 2,
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Guest House Remodeling Postponed
In December we reported that the SLAC Guest House projected limited
availability during renovations planned for January-March. However, we have
since learned that these renovations have been postponed. Users are advised to
make reservations as early as possible to secure a place at the Guest
House. User Reservations
Coronavirus Information and Related Travel Restrictions
There is a global public health emergency regarding an outbreak of
respiratory illness caused by a new strain of coronavirus, 2019 Novel
Coronavirus (2019-nCoV), originating in Wuhan, Hubei Province, China. While the
virus is a serious public health concern, the risk to most people outside China
remains very low.
Stanford University’s Public Health Policy Committee is closely
monitoring developments and provides answers to some of the most pressing
questions about this situation on its website which will be updated as new
information is learned, please see https://ehs.stanford.edu/news/2019-novel-coronavirus-2019-ncov.
Some specific information regarding SLAC operations include:
- Visitors/Users coming from China: The federal
government has temporarily suspended entry into the United States for any
foreign nationals who have traveled in China within the last 14 days.
- Any users, irrespective of nationality, who are
scheduled for beam time and have visited China since January 15 needs to
contact the SSRL User Administration before attempting to come on
Stanford University and SLAC leadership are actively monitoring the
developing situation with respect to the spread of the disease and potential
impacts to lab functions. Site access recommendations will be revisited based
on the best available data and recommendations from the Centers for Disease
User Research Administration
The FY2020 user run will continue through August 10, 2020, with a brief down
time scheduled April 6–14, 2020. See Experimental Run Schedules
Beam Time Requests
- Feb 22, 2020 – Users with active X-ray/VUV proposals who
desire beam time May–Aug 2020 and who have not reached their estimated
shifts are encouraged to submit beam time requests. Remember to submit
separate requests for each beam line, configuration or dates desired.
- Apr 17, 2020 – Macromolecular Crystallography (Jun–Aug
- Mar 1, 2020 – S2C2 Cryo-EM
- Apr 1, 2020 – Macromolecular Crystallography
- May 1, 2020 – X-ray / VUV
Submit beam time requests and proposals through the User
Portal. Questions can be directed to the SSRL User Office or the
CryoEM User Office
The Stanford Synchrotron Radiation Lightsource (SSRL) is a third-generation
light source producing extremely bright x-rays for basic and applied
research. SSRL attracts and supports scientists from around the world who
use its state-of-the-art capabilities to make discoveries that benefit society.
SSRL, a U.S. DOE Office of Science national user facility, is a Directorate of
SLAC National Accelerator Laboratory, operated by Stanford University for the
U.S. Department of Energy Office of Science. The SSRL Structural
Molecular Biology Program is supported by the DOE Office of Biological and
Environmental Research, and by the National Institutes of Health, National
Institute of General Medical Sciences. For more information about SSRL science,
operations and schedules, visit http://www-ssrl.slac.stanford.edu.
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