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Spin- and angle-resolved photoemission (spinARPES)


The principle of operation of modern spintronic devices, such as magnetic tunnel junctions, is based on specific properties of electronic band dispersions, which exist in reciprocal space. High resolution angle-resolved photoemission (ARPES) has become the method of choice to probe the electronic structure of any new material.

Our laboratory based ARPES system [1] is equipped with MBS A-1 angle-resolving hemispherical analyzer, several gas discharge photon sources capable of producing 8.3, 10.0, 11.6, 21.2 and 40.8 eV photons, and helium cooled cryostat capable of cooling the sample down to 15K. Our second system based in DELTA/Dortmund is capable of measuring spin- and angle-resolved photoemission spectra [2].

Since photoemission is a surface sensitive technique all experiments are performed under ultra-high vacuum (UHV) conditions. Surface preparation techniques such as cleaving, sputtering, and annealing are all available under UHV. Ultra thin epitaxial films can be grown by molecular beam epitaxy (MBE), and the system is equipped with other standard equipment such as low energy electron diffraction, Auger-spectrometer, mass spectrometer, quartz balance thickness monitor etc.

Figure shows the three dimensional impression of the electronic structure of an important topological insulator Bi2Te3 measured in our laboratory with 21.2 eV photons and the sample temperature kept at 15K [3].

We are currently upgrading our system with the additional highly efficient spin-polarimeter [4], which will allow semi-simultaneous operation of high resolution angle resolved photoemission in 2D angular map mode, and spin-polarized photoemission in EDC mode.


[1] S. Suga, A. Sekiyama, G. Funabashi, J. Yamaguchi, M. Kimura, M. Tsujibayashi, T. Uyama, H. Sugiyama, Y. Tomida, G. Kuwahara, S. Kitayama, K. Fukushima, K. Kimura, T. Yokoi, K. Murakami, H. Fujiwara, Y. Saitoh, L. Plucinski and C. M. Schneider, “High resolution, low hn photoelectron spectroscopy with the use of a microwave excited rare gas lamp and ionic crystal filters”, Rev. Sci. Instrum. 81, 105111 (2010).

[2] L. Plucinski, A. Oelsner, F. Matthes, and C.M. Schneider, “A hemispherical photoelectron spectrometer with 2-dimensional delay-line detector and integrated spin-polarization analysis”, J. Elec. Spectroscopy 181, 215 (2010).

[3] L. Plucinski, G. Mussler, J. Krumrain, A. Herdt, S. Suga, D. Grützmacher, and C. M. Schneider, “Robust surface electronic properties of topological insulators: Bi2Te3 films grown by molecular beam epitaxy”, Appl. Phys. Lett. 98, 222503 (2011).

[4] M. Escher, N. B. Weber, M. Merkel, L. Plucinski, and C. M.  Schneider, “FERRUM: A New Highly Efficient Spin Detector for Electron Spectroscopy” e-Journal of Surface Science and Nanotechnology 9, 340 (2011).





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