Fast, reversible, and low-power manipulation of the spin texture is crucial fornext generation spintronic devices like non-volatile bipolar memories,switchable spin current injectors or spin field effect transistors. FerroelectricRashba semiconductors (FERSC) are the ideal class of materials for therealization of such devices. Their ferroelectric character enables an electroniccontrol of the Rashba-type spin texture by means of the reversible andswitchable polarization. Yet, only very few materials are established to belongto this class of multifunctional materials. Here, Pb1?xGexTe is unraveled as anovel FERSC system down to nanoscale. The ferroelectric phase transition andconcomitant lattice distortion are demonstrated by temperature dependentX-ray diffraction, and their effect on electronic properties are measured byangle-resolved photoemission spectroscopy. In few nanometer-thick epitaxial heterostructures, a large Rashba spin-splitting is exhibiting a wide tuningrange as a function of temperature and Ge content. This work definesPb1?xGexTe as a high-potential FERSC system for spintronic applications.
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