Publications de Emmanouil Frantzeskakis

From hidden order to antiferromagnetism: Electronic structure changes in Fe-doped URu2Si2

Emmanouil Frantzeskakis, Kevin Huang, Ji Dai

In matter, any spontaneous symmetry breaking induces a phase transition characterized by an order parameter, such as the magnetization vector in ferromagnets, or a macroscopic many electron wave function in superconductors. Phase transitions with unknown o ...

National Academy of Sciences2021

Experimental Observation and Spin Texture of Dirac Node Arcs in Tetradymite Topological Metals

Emmanouil Frantzeskakis, Ji Dai

We report the observation of a nontrivial spin texture in Dirac node arcs, i.e., novel topological objects formed when Dirac cones of massless particles extend along an open one-dimensional line in momentum space. We find that such states are present in al ...

AMER PHYSICAL SOC2021

Quantum interference effects of out-of-plane confinement on two-dimensional electron systems in oxides

Emmanouil Frantzeskakis, Ji Dai

It was recently discovered that a conductive, metallic state is formed on the surface of some insulating oxides. First observed on SrTiO3 (001), it was then found in other compounds as diverse as anatase TiO2, KTaO3, BaTiO3, ZnO, and also on different surf ...

2020

Polarization dependence of angle-resolved photoemission with submicron spatial resolution reveals emerging one-dimensionality of electrons in NbSe3

Helmuth Berger, Marco Grioni, Emmanouil Frantzeskakis, Miguel Angel Valbuena

In materials with nearly commensurate band filling the electron liquid may spontaneously separate into components with distinct properties, yielding complex intra- and interunit cell ordering patterns and a reduced dimensionality. Polarization-dependent an ...

AMER PHYSICAL SOC2019

SmB6 electron-phonon coupling constant from time- and angle-resolved photoelectron spectroscopy

Emmanouil Frantzeskakis, Alberto Crepaldi

SmB6 is a mixed valence Kondo system resulting from the hybridization between localized f electrons and delocalized d electrons. We have investigated its out-of-equilibrium electron dynamics by means of time- and angle-resolved photoelectron spectroscopy. ...

Amer Physical Soc2016

Combined ARPES and STM study of Pb/Au(111) Moiré structure: One overlayer, two symmetries

Harald Brune, Klaus Kern, Marco Grioni, Markus Etzkorn, Emmanouil Frantzeskakis, Alberto Crepaldi

The structural and electronic properties of a Pb monolayer (ML) grown on Au(111) are investigated by scanning tunneling microscopy (STM) and angle resolved photoelectron spectroscopy (ARPES). We find an incommensurate Moire structure with an approximate (5 ...

Amer Physical Soc2013

Two Distinct Phases of Bilayer Graphene Films on Ru(0001)

Harald Brune, Marco Grioni, Stefano Rusponi, Anne Lehnert, Daniela Pacilè, Quentin Dubout, Emmanouil Frantzeskakis, Donat Fabian Natterer

By combining angle-resolved photoemission spectroscopy and scanning tunneling microscopy we reveal the structural and electronic properties of multilayer graphene on Ru(0001). We prove that large ethylene exposure allows the synthesis of two distinct phase ...

Amer Chemical Soc2012

Anisotropic spin gaps in BiAg2-Ag/Si(111)

Klaus Kern, Marco Grioni, Emmanouil Frantzeskakis, Alberto Crepaldi

We present a detailed analysis of the band structure of the root 3 x root 3 R 30 degrees BiAg2/Ag/Si(111) trilayer system by means of high resolution Angle Resolved Photoemission Spectroscopy (ARPES). BiAg2/Ag/Si(111) exhibits a complex spin-polarized elec ...

2012

Anisotropy effects on Rashba and topological insulator spin-polarized surface states: A unified phenomenological description

Marco Grioni, Emmanouil Frantzeskakis

Spin-polarized two-dimensional electronic states have been observed in metallic surface alloys with giant Rashba splitting and at the surface of topological insulators. We study the surface band structure of these systems, in a unified manner, by exploitin ...

2011

Spectroscopic Studies on Semiconducting Interfaces with Giant Spin Splitting

Emmanouil Frantzeskakis

The application of an external magnetic field can lift the spin degeneracy of electronic states through its interaction with the electronic magnetic moment. A closely-related phenomenon is the Rashba-Bychkov (RB) effect where symmetry breaking at surfaces ...

EPFL2010

Band structure scenario for the giant spin-orbit splitting observed at the Bi/Si(111) interface

Marco Grioni, Emmanouil Frantzeskakis

The Bi/Si(111) (root 3 x root 3)R30 degrees trimer phase offers a prime example of a giant spin-orbit splitting of the electronic states at the interface with a semiconducting substrate. We have performed a detailed angle-resolved photoemission spectroscop ...

2010

Silicon Surface with Giant Spin Splitting

Klaus Kern, Marco Grioni, Christian Reinhard Ast, Emmanouil Frantzeskakis

We demonstrate a giant Rashba-type spin splitting on a semiconducting substrate by means of a Bi-trimer adlayer on a Si(111) wafer. The in-plane inversion symmetry is broken inducing a giant spin splitting with a Rashba energy of about 140 meV, much larger ...

American Physical Society2009

Giant spin-orbit splitting in a surface alloy grown on a Si substrate: BiAg2/Ag/Si(111)

Marco Grioni, Emmanouil Frantzeskakis

We report on the formation of a BiAg2/Ag/Si(1 1 1) trilayer system which exhibits a giant Rashba spin-splitting of its surface-localized states and is grown on a semiconducting substrate. Angle-resolved photoelectron spectroscopy (ARPES) results reveal the ...

2009

Tunable Spin Gaps in a Quantum-Confined Geometry

Marco Grioni, Emmanouil Frantzeskakis

We have studied the interplay of a giant spin-orbit splitting and of quantum confinement in artificial Bi-Ag-Si trilayer structures. Angle-resolved photoelectron spectroscopy reveals the formation of a complex spin-dependent gap structure, which can be tun ...

American Physical Society2008

Recent ARPES experiments on quasi-1D bulk materials and artificial structures

Marco Grioni, Emmanouil Frantzeskakis

The spectroscopy of quasi-one-dimensional (1D) systems has been a subject of strong interest since the first experimental observations of unusual line shapes in the early 1990s. Angle-resolved photoemission (ARPES) measurements performed with increasing ac ...

2008