Regensburg 2016 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 48: Poster Session II

MA 48.72: Poster

Donnerstag, 10. März 2016, 15:00–18:00, Poster B1

Experimental realization of a topological p-n junction by intrinsic defect-grading — •Thomas Bathon¹, Simona Achilli², Paolo Sessi¹, Konstantin Kokh³, Oleg Tereshchenko³, and Matthias Bode¹ — ¹Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — ²Fisica, Universita Cattolica di Brescia, via dei Musei 41, 25121 Brescia, Italy — ³Novosibirsk State University, 630090 Novosibirsk, Russia

The extraordinary properties of topological insulators (TIs) are related to linearly dispersing surface states which exhibit chiral spin-momentum-locking. Thereby, backscattering is forbidden and spin currents are intrinsically tied to charge currents. This unconventional spin-texture makes TIs not only fundamentally interesting, but also of great practical importance for applications. Within this framework, the fabrication of topological p-n junctions would represent a pivotal step towards the design of devices with new functionalities.

Here we demonstrate by transport measurements that the different defects inevitably incorporated during the growth process of the prototypical material Bi₂Te₃ result in topological p-n junctions. Atomic-scale STM data combined with ab-initio calculations show that this is the result of the different doping character of the various intrinsic defects. The transition region is found to be as narrow as few tens of nm with a built-in potential of approximately 110 meV.