Atomic and Electronic Structure of a Multidomain GeTe Crystal
Item Type:Journal Article
Citation:Frolov, A.S., Sánchez-Barriga, J., Callaert, C., Hadermann, J., Fedorov, A.V., Usachov, D.Y., Chaika, A., Walls, B., Zhussupbekov, K., Shvets, I.V., Muntwiler, M., Gregoratti, L., Amati, M., Varykhalov, A., Rader, O., Yashina, L.V., Atomic and Electronic Structure of a Multidomain GeTe Crystal, ACS Nano, 2020, 14, 12, 16576–16589
GeTe_paper.pdf (Pre-print (author's copy) - Non-Peer Reviewed) 19.78Mb
Renewed interest in the ferroelectric semiconductor germanium telluride was recently triggered by the direct observation of a giant Rashba effect and a 30-year-old dream about a functional spin field-effect transistor. In this respect, all-electrical control of the spin texture in this material in combination with ferroelectric properties at the nanoscale would create advanced functionalities in spintronics and data information processing. Here, we investigate the atomic and electronic properties of GeTe bulk single crystals and their (111) surfaces. We succeeded in growing crystals possessing solely inversion domains of ∼10 nm thickness parallel to each other. Using HAADF-TEM we observe two types of domain boundaries, one of them being similar in structure to the van der Waals gap in layered materials. This structure is responsible for the formation of surface domains with preferential Te-termination (∼68%) as we determined using photoelectron diffraction and XPS. The lateral dimensions of the surface domains are in the range of ∼10–100 nm, and both Ge- and Te-terminations reveal no reconstruction. Using spin-ARPES we establish an intrinsic quantitative relationship between the spin polarization of pure bulk states and the relative contribution of different terminations, a result that is consistent with a reversal of the spin texture of the bulk Rashba bands for opposite configurations of the ferroelectric polarization within individual nanodomains. Our findings are important for potential applications of ferroelectric Rashba semiconductors in nonvolatile spintronic devices with advanced memory and computing capabilities at the nanoscale.
Russian Science Foundation
Impuls-und Vernetzungsfonds der Helmholtz Gemeinschaft
2017-1-IE02-KA107- 000538 & 2017-1-IE02-KA107-000538
Description:PUBLISHED. This is the submitted version of the work. The full version is available at https://pubs.acs.org/doi/10.1021/acsnano.0c05851
Author: S. Frolov, Alexander; Sánchez-Barriga, Jaime; Callaert, Carolien; Hadermann, Joke; Fedorov, Alexander V.; Usachov, Dmitry Yu.; Chaika, Alexander; Walls, Brian; Zhussupbekov, Kuanysh; Shvets, Igor V.; Muntwiler, Matthias; Gregoratti, Luca; Amati, Matteo; Varykhalov, Andrei; Rader, Oliver; Yashina, Lada V.
Type of material:Journal Article
Series/Report no:ACS Nano;
Availability:Full text available
Keywords:Materials Science, GeTe, Ferroelectricity, Germanium telluride, Ferroelectric domains, Rashba effect, Electronic structure, Surface atomic structure, Domain walls