Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 96: Magnetic Semiconductors
HL 96.5: Vortrag
Freitag, 11. März 2016, 11:00–11:15, H13
Site resolved band structure of a diluted magnetic semiconductor — •Slavomir Nemsak1, Mathias Gehlmann1, Cheng-Tai Kuo2, Tien-Lin Lee3, Lukasz Plucinski1, Claus M. Schneider1, and Charles S. Fadley2 — 1Forschungszentrum Juelich, Germany — 2UC Davis, CA, USA — 3Diamond Light Source, Didcot, GB
Standing wave (SW) photoemission of core-levels and valence electrons at the density-of-states limit has proven to be a very potent and powerful method, especially for investigating electronic properties of the buried interfaces, either solid/solid [Gray et al., EPL 104, 17004 (2013)], but also solid/liquid and liquid/gas [Nemsak et al., Nat. Comm. 5, 5441 (2014)]. The exceptional depth selectivity provides a key to the depth-resolved information, which is very difficult to extract by other, less direct, methods.
The combination of the SW approach and hard X-ray angle resolved photoelectron spectroscopy (HARPES) [Gray et al., Nature Mat. 11, 957 (2012)] takes these efforts one step further. The strengths of the SW-HARPES method are demonstrated on the example of diluted magnetic semiconductor Ga(Mn)As. A strong SW is generated using hard X-ray excitation of ca. 3 keV using the (111) reflection of the undoped GaAs substrate and the 5% Mn-doped thin film with. Due to the uneven occupancy of (111) planes by either Ga(Mn) or As atoms, the element specific band structure can be obtained with a help of the SW modulation in core levels. Apart from the site specific decomposition of the electronic structure, the SW measurement confirmed a substitutional presence of Mn atoms at the Ga sites.