Matthew Warkentin, Robert Thorne and James Sethna have published the first molecular-level understanding of exactly how solutes slow down ice formation with implications in fields ranging from climate physics to cryopreservation and artificial insemination.

Read more in the Chronicle.

Professor of physics Kyle Shen, working with other researchers has performed the first first high-resolution Angle-resolved photoemission spectroscopy (ARPES) measurements of strontium ruthenate.  ARPES is a direct experimental technique to observe the distribution of the electrons in the reciprocal space of solids.  Shen et. al. studied SrRuO3 which is currently utilized as a conductive electrode for ferroelectrics, Schottky diodes, magnetocalorics, and magnetoelectrics.  The paper was published in Physical Review Letters on February 22.

Unsymmetrized FS map for SrRuO3 at T ¼ 20 K integrated within EF  5 meV,
along with E vs kx, ky spectra illustrating the underlying band structure.

Their work showed that strong electron-boson interactions have an important role in the large mass renormalization in SrRuO3. Local magnetic moments in this ruthenate also play an important role in its properties.  Contributing to the results were physics PhD candidate Daniel Shai, John Harter, Eric Monkman and Bulat Burganov.

To read the full article in Physical Review Letters, click here.

Professor of physics Robert Richardson passed away in Ithaca on February 19.  The University’s first Vice Provost for Research, Richardson was exceptionally distinguished serving as director of the Laboratory for Atomic and Solid State Physics, the Kavli Institute at Cornell for Nanoscale Science and most notably as the recipient of the 1996 Nobel Prize in Physics with Prof. David Lee and Prof. Douglas Osheroff (Ph.D. ’73 now a Stanford emeritus).

Richardson’s obituary in the Cornell Chronicle can be found here.

A 48 nm×48 nm topographic image of the Ca-122 surface

Scientists studying high-temperature superconductivity know that the introduction of dopant atoms leads to the development of superconductive behavior.  However there is a lack of experimental work showing what these dopants do to the atomic-scale electronic structure of superconductive materials.  Professor of physics J.C. Séamus Davis has now imaged the effects of these impurity atoms.  His work is published in the February 17 edition of Nature Physics.

Davis’ results show regular pattern of anisotropic scattering of quasiparticles in the substrate that is proportional to the dopant density.

To read the full article in Nature Physics, click here.

Itai Cohen along with PhD students Jesse Silverberg and Matt Bierbaum are researching emergent phenomena in human behavior. Their recent article, which has drawn quite a lot of attention, looks at the collective motion that occurs inside a mosh pit during heavy metal concerts. The authors have developed a model of the behavior dubbed Mobile Active Simulated Humanoids, or MASHers. Check out the Cohen group website for updates on the story and interactive simulations of the MASHers in action.

View story in the press:

NBC, National Geographic, Popular Science, New Scientist, The Atlantic, The Chicago Reader, The Huffington Post (written by co-author J.L.S.)

Photo credit: Ulrike Biets

Materials scientists at Cornell have taken another step closer to high-temperature superconductors. Working with strontium-lanthanum cuprates, professor or physics Kyle Shen and collaborators created a superconductor at 100 Kelvin (-280 F, which is pretty warm for these researchers). The work was published in the December 27 Physical Review Letters.

The group was observing the properties of strontium-lanthanum cuprates, nicknamed the “infinite layer” when doped with extra electrons. When cooled the electrons undergo a phase transition and become superconducting, which means electrons can flow freely through them without resistance.

Scientists have previously studied strontium-lanthanum cuprates that are hole-doped – meaning electrons are removed from the material. It was assumed that the materials should respond in the same way to hole doping and electron doping. Shen’s results now show this needs to be studied further.

To read the paper in Physical Review Letters, click here.

To read more about Shen’s work in the Cornell Chronicle, click here.

Sol Gruner’s work on x-ray detectors is the featured cover article in this month’s Physics Today. In the article Prof Gruner outlines the development of x-ray detectors as guided by experimental opportunity—or, more specifically, the need for enhanced resolution in some aspects of the measurement.

View Article »

A team of LASSP researches, led by Prof Paul McEuen in the Kavli Institute at Cornell for Nanoscale Science,  have been using graphene to understand how electrons cool. Using novel methods they observed for the first time how electrons slowly cool in single-atom thick sheets of graphene.

Find out more at the Chronicle: http://www.news.cornell.edu/stories/Dec12/grapheneCool.html

And the full Nature Physics article is available at http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys2493.html

Prof. of physics Rob Thorne stepped in to remedy these issues by creating new plates and tools for this work.  His patent was reported in the December 2012 issue of Scientific American.  Thorne’s new tools have curvature which makes them thin yet strong and his plates replace wells with micropatterned film.

For more information from Scientific American, click here.