18 research outputs found
Simulating Ion Scattering Trajectories on a Stepped Surface
Surfaces cut in the (111) direction exhibit isolated surface states, as the conduction band does not have any states with momentum along the z axis. These states however, are un localized, and very difficult to interact with via ion scattering. STM studies have shown that these surface states can be localized, by cutting the lattice such that it contains steps of (111) surfaces. These localized states might then be able to be interacted with via ion beam studies
First Multicharged Ion Irradiation Results from the CUEBIT Facility at Clemson University
A new electron beam ion trap (EBIT) based ion source and beamline were recently commissioned at Clemson University to produce decelerated beams of multi- to highly-charged ions for surface and materials physics research. This user facility is the first installation of a DREEBIT-designedsuperconducting trap and ion source (EBIS-SC) in the U.S. and includes custom-designed target preparation and irradiation setups. An overview of the source, beamline, and other facilities as well as results from first measurements on irradiated targets are discussed here. Results include extracted charge state distributions and first data on a series of irradiated metal-oxide-semiconductor (MOS) device targets. For the MOS devices, we show that voltage-dependent capacitance can serve as a record of theelectronic component of ion stopping power for an irradiated, encapsulated oxide target
Generic First Order Orientation Transition of Vortex Lattices in Type II Superconductors
First order transition of vortex lattices (VL) observed in various
superconductors with four-fold symmetry is explained microscopically by
quasi-classical Eilenberger theory combined with nonlocal London theory. This
transition is intrinsic in the generic successive VL phase transition due to
either gap or Fermi velocity anisotropies. This is also suggested by the
electronic states around vortices. Ultimate origin of this phenomenon is
attributed to some what hidden frustrations of a spontaneous symmetry broken
hexagonal VL on the underlying four-fold crystalline symmetry.Comment: 4 pages, 5 figures, some typos are correcte
Perspectives on Astrophysics Based on Atomic, Molecular, and Optical (AMO) Techniques
About two generations ago, a large part of AMO science was dominated by
experimental high energy collision studies and perturbative theoretical
methods. Since then, AMO science has undergone a transition and is now
dominated by quantum, ultracold, and ultrafast studies. But in the process, the
field has passed over the complexity that lies between these two extremes. Most
of the Universe resides in this intermediate region. We put forward that the
next frontier for AMO science is to explore the AMO complexity that describes
most of the Cosmos.Comment: White paper submission to the Decadal Assessment and Outlook Report
on Atomic, Molecular, and Optical (AMO) Science (AMO 2020
Perspectives on Astrophysics Based on Atomic, Molecular, and Optical (AMO) Techniques
About two generations ago, a large part of AMO science was dominated by experimental high energy collision studies and perturbative theoretical methods. Since then, AMO science has undergone a transition and is now dominated by quantum, ultracold, and ultrafast studies. But in the process, the field has passed over the complexity that lies between these two extremes. Most of the Universe resides in this intermediate region. We put forward that the next frontier for AMO science is to explore the AMO complexity that describes most of the Cosmos