microprobe ARPES

SPELEEM applications , LEEM , energy filtered XPEEM , XAS-PEEM , microprobe-ARPES

microprobe ARPES

Along with real space imaging, the SPELEEM microscope is capable of micro-probe diffraction imaging. In this operation mode, the SPELEEM images the backfocal plane of the objective lens. Depending whether electrons or photons are used to probe the surface, the SPELEEM can enable laterally restricted low energy electron diffraction (microprobe-LEED) and angle resolved photoemission electron spectroscopy (microprobe-ARPES) measurements. In ARPES mode, the full angular emission pattern can be imaged up to a photoelectron parallel momentum of about 2 inverse angstroms. The ARPES measurements are restricted to an area of about 2 microns in diameter. This region is selected by inserting an aperture (field limiting or selected area aperture) in the beam separator, that is in first image plane encountered along the imaging optics column of the microscope. In this manner, the microscope enables measurements on samples that are homogeneous over an area of about 3 square microns. In microprobe-ARPES, the photon energy hν is kept fixed, while kinetic energy Ekin of the photoelectrons is selected by scanning the start voltage. The energy resolution of the SPELEEM depends on the width of the selected analyzer energy slit. Routinely, the SPELEEM achieve an energy resolution of about 300 meV, a value that can be improved to less than 200 meV by decreasing the pass energy of the analyzer. Based on the transfer width of the microscope in LEED mode, we estimate an angular resolution of 0.06 inverse Angstroms.


SPELEEM: combining LEEM and spectroscopic imaging;
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Making angle-resolved photoemission measurements on corrugated monolayer crystals: Suspended exfoliated single-crystal graphene;
K. R. Knox, A.Locatelli, M.B. Yilmaz, D. Cvetko, T.O. Menteş, M.Á. Niño, P. Kim, A. Morgante, and R.M. Osgood, Jr.;
Phys. Rev. B 84, 115401 (2011).
doi: 10.1103/PhysRevB.84.115401

Spectromicroscopy of single and multilayer graphene supported by a weakly interacting substrate;
K.R. Knox, S. Wang, A. Morgante, D. Cvetko, A. Locatelli, T.O. Menteş, M.Á. Niño, P. Kim, and R.M. Osgood Jr.;
Phys. Rev. B 78, 201408 (2008).
doi: 10.1103/PhysRevB.78.201408

Ultima modifica il Mercoledì, 03 Luglio 2013 15:30