In collaboration with the Qiu group at Yale, we have posted a new paper on excitons in TMD heterostructures. Using time-resolved ARPES in combination with ab initio theory, we determine the mixture of excitons produced in MoSe2/WS2 bilayers after above-gap excitation at different twist angles.
Our results indicate a much more complicated, and richer, story than previously reported, involving lattice strain and a mixture of inter-layer and intra-layer excitons with different binding energies.
Our web server died again, of course right during proposal season. Ugh. This time it was a Raspberry Pi. From now no more DIY web servers. We have migrated to a professional solution hosted by GoDaddy, with new domain allisongroup.net. I have high hopes for you, GoDaddy.
Stay tuned for more updates to the website reflecting current research efforts soon!
We have posted a new “perspective” article on cavity-enhanced HHG for high-performance photoemission experiments. It can be found here: https://arxiv.org/abs/2410.11589
Michael Wahl has completed his M.S.I. degree in the Allison lab, developing tunable frequency combs with arbitrary (0-60.5 MHz) for the Allison lab tr-ARPES instrument. This is the last piece of the tr-ARPES laser puzzle.
Mike is off now to Boulder, CO to further work on frequency combs in the research group of Prof. Scott Diddams.
With the Levine group, we have posted a new paper about simulating transient absorption spectroscopy from first principles.
We have posted a new paper regarding imaging pseudospin dynamics in graphene. Working at the low excitation fluences enabled by our unique tr-ARPES instrument, we are able to vary the relative importance of electron-electron and electron-phonon scattering on the dynamics and also momentum-resolve the nascent photoexcited electrons before they relax. These are very challenging measurements due the very short carrier lifetimes in graphene and the need to resolve fine momentum-space features of the distributions.
Myles Silfies has successfully defended his dissertation and completed his Ph. D. Many thanks to committee members Cyrus Dreyer, Chris Johnson, and A. J. Fleisher for serving on Myles’ committee. Also thanks to Tom Weinacht (pictured at left) for helping liberate the champagne.
Myles will be working on putting frequency combs in space for Space Dynamics Laboratory in Albuquerque, NM.
Allison lab postdoc Alice Kunin will start as an assistant professor at Princeton in Jan. 2024 where she will continue to develop advanced photoelectron spectroscopy techniques. Princeton has made a news post with more details.
Our work resolving valley polarization dynamics in monolayer WS2 is now featured as a DOE office of Science Highlight.
We have posted a new paper regarding the ultrafast dynamics salicylideneanaline, combining CE-TAS measurements with ab initio theory from the Levine group. The paper can be found here: https://arxiv.org/abs/2306.05645
