Alloying as a tool to chemically tune properties of ferroelectric Rashba semiconductors.

Nessi L., Fagiani F., Cantoni M., Belponer F., Cecchi S., Vinai G., Mondal D., Mazzola F., Fujii J., Vobornik I., Calarco R., Delodovici F., Picozzi S., Bertacco R., Rinaldi C.
  Martedì 13/09   09:00 - 13:30   Aula D - Marianna Ciccone   II - Fisica della materia   Presentazione
GeTe and SnTe are key prototypes of ferroelectric Rashba semiconductors, materials in which the ferroelectric polarization direction governs Rashba spin texture, offering an unprecedent, non-volatile electric control over spin-to-charge conversion. GeTe has been widely investigated, while ferroelectric SnTe is expected to show a larger spin-to-charge conversion efficiency thanks to a giant intrinsic spin Hall conductivity in 2D. Unfortunately, the Curie temperature of SnTe below $300 {K}$ represents a limiting factor for applications. A promising route is provided by alloying the two chalcogenides in the ternary compound $Sn_{x}Ge_{1-{x}}Te$, where Ge may allow for stabilization of the ferroelectric phase up to room temperature. In this contribution, we experimentally study the band structure and ferroelectric properties of SnGeTe thin films $vs.$ composition and temperature, with the support of $ab initio$ calculations. The tunability of both Rashba spin-orbit coupling and ferroelectricity above room temperature on a wide range of chemical compositions opens the route to the chemical engineering of the properties of ferroelectric Rashba semiconductors.