2014 Spring Physics Graduate Colloquium Series: Indra Ghimire/Brian Ko

DateMarch 28, 2014Time3:35 - 5:00 pm
LocationBaylor Sciences Building, Room E.125
Description
Indra Ghimire

The Electron- Boson Coupling in Superconducting FeSe Films Imaged by Scanning Tunneling Microscope

The bosonic mode in the local quasiparticle density of states of superconducting FeSe films appears below Tc as a "dip hump" feature of energy Ω~ 4.7k bTc beyond the superconducting gap Δ. Scanning tunneling spectroscopy spectra on strained region of the film shows simultaneous decrease in Δ and Ω contrasting the previous studies where there exists an anti co-relation of Ω with Δ. In order to resolve this discrepancy and to give the unified picture of the electron-boson coupling in unconventional superconductors, a local strong coupling model is found. This talk is based on the PRL paper “Imaging the Electron-Boson Coupling in Superconducting FeSe Films using a Scanning Tunneling Microscope”.

Phys. Rev. Lett. 112, 057002 (2014) Published 6 February 2014

Brian Ko

Laser-Driven Nuclear Reactions through Proton Recollision

Electron recollision by a laser field is a central concept in strong-field physics. However, the same idea can be applied to protons with a sufficiently-powered field and produce various nuclear reactions, including the 15N(p,α)12C reaction observed in nuclear astrophysics. Lotstedt and Midorikawa report on the results of their simulations of this event, in which the Hydrogen atoms of 15NH3 are liberated from the molecule using a laser field, which are then re-focused into the nucleus via an electric field. The effects of controlling the carrier-envelopephase (CEP) and the alignment of the molecule are also investigated.

http://dx.doi.org/10.1103/PhysRevLett.112.093001

For more information, please contact: Dr. Ken Park 254-710-2282

PublisherDepartment of Physics
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