TY  - JOUR
A1  - Rinaldi, Christian
A1  - Varotto, Sara
A1  - Asa, Marco
A1  - Slawinska, Jagoda
A1  - Fujii, Jun
A1  - Vinai, Giovanni
A1  - Cecchi, Stefano
A1  - Di Sante, Domenico
A1  - Calarco, Raffaella
A1  - Vobornik, Ivana
A1  - Panaccione, Giancarlo
A1  - Picozzi, Silvia
A1  - Bertacco, Riccardo
T1  - Ferroelectric Control of the Spin Texture in GeTe
JF  - Nano Letters
N2  - The electric and nonvolatile control of the spin texture in semiconductors would represent a fundamental step toward novel electronic devices combining memory and computing functionalities. Recently, GeTe has been theoretically proposed as the father compound of a new class of materials, namely ferroelectric Rashba semiconductors. They display bulk bands with giant Rashba-like splitting due to the inversion symmetry breaking arising from the ferroelectric polarization, thus allowing for the ferroelectric control of the spin. Here, we provide the experimental demonstration of the correlation between ferroelectricity and spin texture. A surface-engineering strategy is used to set two opposite predefined uniform ferroelectric polarizations, inward and outward, as monitored by piezoresponse force microscopy. Spin and angular resolved photoemission experiments show that these GeTe(111) surfaces display opposite sense of circulation of spin in bulk Rashba bands. Furthermore, we demonstrate the crafting of nonvolatile ferroelectric patterns in GeTe films at the nanoscale by using the conductive tip of an atomic force microscope. Based on the intimate link between ferroelectric polarization and spin in GeTe, ferroelectric patterning paves the way to the investigation of devices with engineered spin configurations.
KW  - Germanium telluride
KW  - Rashba effect
KW  - ferroelectricity
KW  - spin-orbitronics
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226294
VL  - 18
IS  - 5
ER  - 
TY  - JOUR
A1  - Di Sante, Domenico
A1  - Erdmenger, Johanna
A1  - Greiter, Martin
A1  - Matthaiakakis, Ioannis
A1  - Meyer, René
A1  - Fernandez, David Rodríguez
A1  - Thomale, Ronny
A1  - van Loon, Erik
A1  - Wehling, Tim
T1  - Turbulent hydrodynamics in strongly correlated Kagome metals
JF  - Nature Communications
N2  - A current challenge in condensed matter physics is the realization of strongly correlated, viscous electron fluids. These fluids can be described by holography, that is, by mapping them onto a weakly curved gravitational theory via gauge/gravity duality. The canonical system considered for realizations has been graphene. In this work, we show that Kagome systems with electron fillings adjusted to the Dirac nodes provide a much more compelling platform for realizations of viscous electron fluids, including non-linear effects such as turbulence. In particular, we find that in Scandium Herbertsmithite, the fine-structure constant, which measures the effective Coulomb interaction, is enhanced by a factor of about 3.2 as compared to graphene. We employ holography to estimate the ratio of the shear viscosity over the entropy density in Sc-Herbertsmithite, and find it about three times smaller than in graphene. These findings put the turbulent flow regime described by holography within the reach of experiments. Viscous electron fluids are predicted in strongly correlated systems but remain challenging to realize. Here, the authors predict enhanced effective Coulomb interaction and reduced ratio of the shear viscosity over entropy density in a Kagome metal, inferring turbulent flow of viscous electron fluids.
KW  - coupling-constant dependence
KW  - shear viscosity
KW  - electron
KW  - resistance
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230380
VL  - 11
ER  -