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Davis group finds magnetic disorder in topological insulators

To better understand topological insulators (TIs) and why they weren't living up to their potential Seamus Davis's group at Cornell and Brookhaven National Lab studied them with their scanning tunneling microscope. What they found is the magnetic disorder at the surface was preventing the smooth flow of electrons.

Read more in the Chronicle and their Feb 3 article in Proceedings of the National Academy of Sciences.

Scanning tunnelling microscope image of a 47-nanometer square area of the surface of a topological insulator showing variations in the Dirac-mass gap

Katja Nowack joins LASSP Faculty and starts a SQUID lab

We are thrilled to welcome Assistant Professor of Physics Katja Nowack to Cornell, joining the faculty in LASSP and the Physics Department. As Prof Nowack gets settled in one of her biggest goals will be to construct her lab in PSB featuring a Superconducting QUantum Interference Device or SQUID. Using the SQUID, Nowack plans to explore emergent order and phenomena in a diverse set of quantum materials. The new lab will have opportunities for postdocs, graduate students and undergraduate students.

Prof Nowack’s husband, Iwijn De Vlaminck, is a very talented biophysicist/bioengineer who is also joining Cornell to work in BME with labs in Clark.

If you see them around please give them a warm welcome!

Katja Nowack

Eun-Ah Kim and Seamus Davis groups find 'fingerprint' for high-temperature superconductor

Eun-Ah Kim along with Seamus Davis have isolated a "fingerprint" that identifies specific fluctuations in electrons that force them into pairs, causing their host material, in this case, a high-temperature superconductor called lithium iron arsenic, to make way for free-flowing, resistance-free electron pairs.

Check out the full article in Nature Physics.

Highlights of the paper are in the Chronicle.

 

Video: Comparison between theory (left) and experiment (right) of energy evolution of quasi-particle interference imaging demonstrating fingerprints of spin-fluctuation effects on quasi-particles of a High temperature superconductor LiFeAs.

Image: Quasiparticle Interference (QPI) imaging technique reveals that electron-boson interaction in LiFeAs superconductivity has momentum-space anisotropic self-energy 'fingerprint' of antiferromagnetic spin fluctuations.

Quasiparticle Interference (QPI) imaging technique reveals that electron-boson interaction in LiFeAs superconductivity has momentum-space anisotropic self-energy 'fingerprint' of antiferromagnetic spin fluctuations

John Heron, Dan Ralph, and Darrell Schlom make a breakthrough in instant-on computing

John Heron, a postdoc in Dan Ralph and Darrell Schlom's research groups, has made a breakthrough in room-temperature magnetoelectric memory device.

Read more in:

The Chronicle

Nature: News and Views

Full article in Nature.

conceptual illustration of magnetization reversal

Tomás Arias - Active Learning Initiative is taking teaching into the future

Prof Tomás Arias is the physics lead for the Active Learning Initiative (ALI) in the College of Arts and Sciences. The ALI uses a combination of the flipped classroom learning method with high-tech tools to engage students in learning. The newly redesigned courses have just completed thier first semester and the feedback is excellent.

“What sold me on the active learning mode,” says Arias, “is that it gave us more time in class to share the joy of doing physics – because at the end of the day, people learn when they’re happy and engaged.”

Read more about the ALI and what other's are saying in the Chronicle.

Tomas Arias

Ashcroft's work on superconductivity leads to record breaking high temperature

Prof Neil Ashcroft's work on the superconducting potential of hydrogen compounds has led to a record breaking high temperature superconductor. Using hydrogen sulphide, researchers at Max Planck Institute for Chemistry in Mainz, Germany measured supercondonductivity beginning at 190 K (–83 ˚C). The previous record using cuprates was 164 Kelvin (–109 ˚C).

Read more in Nature News

By Julien Bobroff (user:Jubobroff), Frederic Bouquet (user:Fbouquet), Jeffrey Quilliam, LPS, Orsay, France