engleski

Mobile carriers generated by Ar+ ion-etching of SrTiO_3 single crystals

The future developments of new spintronic devices require high mobility 2DEG to inject and manipulate spins. Recently, such high mobility electron gas has been reported in the LaAlO_3/SrTiO_3 system and attributed to charge transfer at the polar interface. Such oxide based 2DEG is promising since it could be combined with other oxide materials taking advantage of their attractive versatility and multifunctional character. In this charge transfer mechanism the carrier concentration is very high, about 10^21 cm^(-3) and presents a moderate mobility compared to doped SrTiO3 single crystal. An alternative way to obtain high mobility electron gas while controlling the carrier concentration and its extension is by ion etching. We will present analysis of the distribution of defects and mobile carriers generated by means of preferential ion-beam etching of SrTiO_3 single crystals by combining positron annihilation spectroscopy (PAS), conductive-tip atomic force microscopy (CT-AFM) and low temperature magnetotransport. We demonstrate that vacancies generated at the surface by room-temperature ion irradiation diffuse on the micron scale and that consequently, carriers are distributed on the same scale.

spintronics; STO heterostructures; high mobility electron gas; ion etching

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