Giant Rashba-Type Spin Splitting in Ferroelectric GeTe(111)

The Rashba effect as an electrically tunable spin-splitting is anticipated to be the key for semiconductor-based spintronics. It has been pursued in semiconductor heterostructures, where advanced experiments found tunable spin signals at low temperature.
 
 M. Liebmann et al.,   Advanced Materials (2015), doi: 10.1002/adma.201503459

 

Recently, bulk spin splittings came back into focus and bulk Rashba bands have been found in the layered polar semiconductors BiTeCl and BiTeI. While these Rashba bands are not tunable by external fields, an electrically switchable bulk-Rashba system has been discovered theoretically: the room-temperature ferroelectric semiconductor GeTe (Curie temperature: ≈700 K, polarization: 64–70 μC cm−2). Such a material would lead to a nonvolatile control of the Rashba induced spin precession and appears to be scalable, since the ferroelectricity in GeTe persists down to the nm-scale. In addition, the large separation of the two spin branches by about 0.19 Å−1 implies a complete rotation of spins within ≈3.5 nm only (Rashba parameter α ≈ 5 eV Å) pointing to a small footprint of possible spin-transistors.

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Advanced Materials (2015), doi: 10.1002/adma.201503459



Last Updated on Thursday, 24 February 2022 15:42