Abbamonte Group

Department of Physics and Seitz Materials Research Laboratory

M-EELS in a Box

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The M-EELS experiment is down for six weeks as the ESCO project to rebuild the HVAC system for the entire MRL building moves to our floor. The whole instrument is now encased in a giant plywood box to protect it from dust and mishaps. We hope to be recommissioning the instrument in the middle of March. No new science will happen until early May.

Discovery of “Excitonium”

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We just published a paper finally demonstrating that TiSe2 contains a Bose condensate of excitons. The experimental signature is a soft plasmon that falls to zero frequency at Tc. Bert Halperin and Maurice Rice nicknamed this phase “excitonium” in their  1968 Rev. Mod. Phys. paper to emphasize the physical picture of an exciton condensate as an electronic crystal. This discovery, which we believe should be viewed as a landmark in our field, was done using our new M-EELS technique (see Sean’s paper, below).

The media frenzy over this discovery has been unreal, surpassing our wildest expectations. Some of the better written articles may be found in Newsweek, The Independent, and the The Daily Mail. Here is a polished video on YouTube.

Here’s a link to the article in Science.

The x-ray machine has moved!

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Our low-temperature crystallography instrument has a new home. It now lives in a dedicated space in 117 MRL, where it will be used by many research groups for decades to come. Stella Sun and Sangjun Lee did a great job moving the equipment, and thanks go to Youli Li for helping with the alignment and calibration.

Beam time at qRIXS

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We did our first experiment on qRIXS, the world’s first fully angle-resolved soft RIXS spectrometer, which is under development at the Advanced Light Source. This thing will open up a new approach to studying valence band excitations in materials.

Find out more.

Anshul’s paper on Cu-doped TiSe2

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Anshul’s TiSe2Cux paper appeared in Phys. Rev. Lett.. This study shows that superconductivity in copper-doped materials is associated with an incommensurate phase, just as do materials subjected to hydrostatic pressure.

Read it here.