APE

Advanced Photoelectric Effect experiments

The APE concept is based on a state-of-the-art surface science laboratory as a support facility for advanced spectroscopies at two distinct beamlines (APE-LE and APE-HE) using polarized synchrotron radiation in the ultraviolet and soft X-ray range from the Elettra storage ring. APE is a facility for spectroscopic investigation of solid surfaces and nanostructured matter where a number of spectroscopic techniques (ARPES (with Omicron-Scienta DA30 analyzer and in spin-resolved mode), XAS, XMCD/LD, XPS, in-operando and ambient pressure spectroscopy) is coupled with sophisticated off-line preparation/growth and characterization tools (PLD/MBE, atomically resolved STM, LEED-Auger, magneto-optical Kerr effect).

Research highlights / APE-LE Publications / APE-HE Publications / APE Publications

Evidence of magnetism-induced topological protection in the axion insulator candidate EuSn2P2

By combining chemical and magnetic-state sensitive electron and X-ray spectroscopies with first-principle calculations we reveal that EuSn2P2 holds the characteristics of an axion insulator and displays “hidden” electronic properties arising from its layer-dependent ferromagnetic character.
G. M. Pierantozzi et al., PNAS 119 (4) e2116575119 (2022)

Mitrofanovite Pt3Te4: A Topological Metal with Termination-Dependent Surface Band Structure and Strong Spin Polarization

By combining spin- and angle-resolved photoemission spectroscopy, scanning tunneling microscopy/spectroscopy, and density functional theory, we discover surface-termination-dependent topological electronic states in the recently discovered mitrofanovite Pt3Te4.
J. Fujii et al., ACS Nano, 15, 9, 14786 (2021)

High-frequency rectifiers based on type-II Dirac fermions

Here, we demonstrate high-frequency rectification driven by skew scattering in type-II Dirac semimetal NiTe2-based devices that display a remarkably high sensitivity even at frequencies higher than those limited by the transit-time, owing to the contribution of topologically protected surface and bulk bands. Due to the presence of the type-II Dirac nodes close to the Fermi energy and the topological surface states, NiTe2 features high mobility and broadband fast response in the high frequency region.
L. Zhang et al., Nature Communications 12, 1584 (2021)

Kitkaite NiTeSe, an Ambient-Stable Layered Dirac Semimetal with Low-Energy Type-II Fermions with Application Capabilities in Spintronics and Optoelectronics

Here, it is shown that kitkaite (NiTeSe) represents an ideal platform for type-II Dirac fermiology based on spin-resolved angle-resolved photoemission spectroscopy and density functional theory. Precisely, the existence of type-II bulk Dirac fermions is discovered in NiTeSe around the Fermi level together with the presence of topological strongly spin polarized surface states.
I. Vobornik et al., Adv. Funct. Mater. 31, 2106101 (2021)

Radial Spin Texture of the Weyl Fermions in Chiral Tellurium

We discuss the unconventional spin polarization of the Weyl fermions, which we measured by means of spin- and angle-resolved photoelectron spectroscopy. The exotic alignment of the spins around the Weyl points is a consequence of the chiral symmetry and a fundamental ingredient of the magneto-electric effect. G. Gatti et al., Phys. Rev. Lett. 125, 216402 (2020)

Weyl-like points from band inversions of spin-polarised surface states in NbGeSb

We demonstrate how the enhanced spin-orbit coupling leads to the development of pronounced Rashba-like spin splittings and show, both experimentally and via ab initio calculations, how this leads to a rich crossing structure of the spin-polarised surface states. I. Markovic et al., Nature Communications 10, 5485 (2019)

Ferroelectric Control of the Spin Texture in GeTe

We provide the experimental demonstration of the correlation between ferroelectricity and spin texture in GeTe, the parent compound of ferroelectric Rashba semiconductors.

C. Rinaldi et al., Nano Lett. 2018, 18, 2751−2758

Ubiquitous formation of bulk Dirac cones and topological surface states from a single orbital manifold in transition-metal dichalcogenides

We demonstrate how various states that occur in transition metal dichalcogenides naturally arise within a single p-orbital manifold as a general consequence of a trigonal crystal field, and as such can be expected across a large number of compounds.
M.S. Bahramy et al., Nature Materials 17, 21-28 (2018)

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APE within

From 2013 APE became an integral part of NFFA-Trieste open access facility that allowed for the integration of an extra suite of growth (PLD, MBE) and analysis chambers with the APE beamlines. Within NFFA also our spectroscopic tools were further upgraded and now include in-operando and near ambient spectroscopies at APE-HE and spin-resolved ARPES at APE-LE.
(see VESPA: Very Efficient Spin Polarization Analysis in Journal of Synchrotron Radiation).

Experimental techniques

User Area

Proposal Submission

We invite our users and collabrators to discuss their proposals with the beamline local contacts well in advance before the submission deadline. This is crucial for a careful assesment of the experiment feasibility and may lead to improvements in the proposed experimental plan.
Please note that APE-HE and APE-LE accept proposals independently. If your experiment needs the involvement of both beamlines, please follow the submission procedure explained here.

Call for proposals

The deadline for proposal submission for beamtime allocation is to be announced

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Ultima modifica il Venerdì, 10 Marzo 2023 15:08