Angle Resolved Photoelectron Spectroscopy

Electronic & Chemical & Magnetic Characterization (Electron spectroscopy)

Due to the upcoming SLS 2.0 upgrade this technique will be unavailable at PSI until further notice.

Angle Resolved Photoemission (ARPES) allows to measure directly the electronic band structure of crystalline solids. It is based on the photoelectric effect: the electron inside the solid absorbs energy and (negligible) momentum from the incoming photon and is ejected in vacuum where it is detected retrieving information about its initial state energy, momentum and spin. State of the art electron energy and momentum analyzers, and high energy resolution and polarization control of the exciting light are needed for resolving the fine electronic structure. Adding efficient spin-polarization measurement to ARPES, i.e. measuring Spin Polarized-ARPES at uncompromised energy and momentum resolution will enable addressing the study of the magnetic properties of surfaces, interfaces and nanostructures, as well as the spin-orbit coupling effects that determine the spin texture of the surface bands in complex materials of interest for their potential in spintronics.

provided at NFFA-Europe laboratories by:

ICN2

Spain

Uni-NG

Slovenia

provided at Large Scale Facilities by:

CNR-IOM (TS)

Italy

PSI

Switzerland

SOLEIL

France

ALBA

Spain

CNR-IOM (TS)

Italy

ARPES, XPS - Low Energy APE Beamline @ Elettra Synchrotron

Applications

Fermi surface mapping/tomography, spin-resolved ARPES, shallow core XPS

Source

Elettra synchrotron, Apple II Quasi-Periodic undulator; variable polarization (horizontal, vertical, circular ±); flux on sample @ 10µm slits (ph./s) >2 x 1011; beam size on the sample 150x50 (HxV, µm2)

Source Energy Range

8-120 eV

Detection

VG Scienta DA30 analyzer; spin detection based on very low energy electron diffraction (VLEED) from magnetic surface oxide targets

Overall Energy Resolution

(E/dE) 30000

Sample

T range: 15-300 K

Other Capabilities

Preparation chamber with 3 heating stages: HT (RT- 2000K), WT (170K - 900K), LT (RT - 700K); ion gun; 3 evaporator ports (CF40); gas inlet leak valve; LEED+AES (Omicron SPECTALEED)

Additional Tools

MOKE magnetometry: Transversal (Hmax=600 Oe), Polar (Hmax=3000 Oe), 3D (Hmax=80 Oe); atomic resolution STM (room temperature, ETH-Z built)

CNR-IOM (TS)

Italy

ARPES, XPS - BACH Beamline @ Elettra Synchrotron

Applications

Soft-x-ray-VUV and resonant angle-resolved photoelectron spectroscopy, resonant photoelectron diffraction, resonant x-ray photoemission spectroscopy, fast photoemission with selectable polarization; core levels, valence band, work function, Auger, surface and bulk band dispersion, empty states in the conduction band, magnetic remanence, strain in thin films, time-resolved spectral evolutions during surface reactions

Source

Elettra synchrotron, Apple II undulators; variable polarization (horizontal, vertical, circular ±); beam size on the sample 350x350 (HxV, µm2); vertical size can be reduced on request; flux on sample @ 10µm slits (best resolution) (ph./s) 2 x 1012 -6 x 1010

Source Energy Range

35-1650 eV

Detection

VG Scienta R3000 analyzer with slit(s) perpendicular to the scattering plane

Overall Energy Resolution

(E/dE) 20000-5000

Sample

Many samples can be accomodated in a 25x25 mm2 area; T range: 50-1200 K (PID-controlled)

Other Capabilities

Both preparation and main chambers with heating stages (e-beam, direct current, PBN), ion gun (VG), 4 evaporator ports (CF40), gas inlet valve (variable leak valve), diamond file scraper, cleaver; evaporators for organic molecules; e-beam evaporators (Omicron) for metals (evaporation at low sample temperatures is also possible); LEED (OciLEED)

Additional Tools

XAS is possible in the same chamber; quick XPS acquisition mode (300 ms per spectrum); 4 degree-of-freedom manipulator (rotation axis perpendicular to the scattering plane); possibility to measure at T>300 K; electrical Insulation of the sample: possibility to apply a voltage and measure the work function; possibility to superimpose synchrotron beam to external light sources to study photoinduced phenomena

Environment

Base pressure: UHV

ICN2

Spain

ARPES

Applications

Band mapping, Fermi Surface

Source

SPECS UVS 300 UV light with monochromator for He I (21.2 eV) and He II (40.8eV)

Source Energy Range

0-18eV or 0-38eV

Detection

SPECS PHOIBIOS-150 analyser

Overall Energy Resolution

Angular resolution of 0.5 deg and total energy resolution down to 3meV

Sample

T down to 80K, heating to 700K

Other Capabilities

Preparation chamber equipped with heating stage (e beam), sputter gun, load lock, LEED, gas inlet leak valve and 3 evaporation ports

Environment

UHV

PSI

Switzerland

ARPES, RIXS - ADRESS Beamline @ Swiss Light Source Synchrotron

Applications

Soft-X-ray radiation, Resonant Inelastic X-ray Scattering (RIXS) and ARPES

Source

Fixed-gap undulator, circular and 0-180o variable linear polarization, flux on sample up to 1013 ph/s/0.01%BW/400 mA, spot size 10x74 µm2 (ARPES); 4x52 µm2 (RIXS)

Source Energy Range

300 - 1600 eV

Detection

PHOIBIOS-150 analyser, constant angular dispersion through the whole operative energy range

Overall Energy Resolution

Better than 0.07o at 1 keV; up to 33000 (E/ΔE, 1 keV)

Sample

Temperatures down to 10.5 K

Other Capabilities

Transfer chamber equipped with LEED, load-lock, low-T cleavage, preparation chamber: gas exposure, ion bombardment, heating up to 1000oC, and thin film deposition

Additional Tools

RIXS endstation available

Environment

UHV

Scanning/Positioning

CARVING manipulator

PSI

Switzerland

HRPES, SARPES - SIS Beamline @ Swiss Light Source Synchrotron

Applications

The Surface and Interface Spectroscopy (SIS) beamline provides a state-of-the-art experimental set-up to study the electronic band structure of novel complex materials by spin- and angle-resolved photoelectron spectroscopies. The beamline has been designed for the energy range from 10 to 800 eV with high flux, high resolution, variable polarization, and low high-harmonic contamination

Source

EM crossed field undulator, linear horizontal (10 - 800 eV), linear vertical (100 - 800 eV), circular left/right (50-800 eV) , flux at 200 eV 2x1013 ph/s/0.1%BW/0.4A, spot size on sample at 200 eV 50μm x 100μm

Source Energy Range

10 - 800 eV

Detection

VG-SCIENTA R4000 photoelectron spectrometer for a total angular acceptance of 30 degrees

Overall Energy Resolution

Up to 10000 (E/ΔE)

Sample

Temperatures down to 10 K and up to 400 K, sample dimensions: diameter < 10mm, thickness ~0.1 - 3mm

Other Capabilities

In-situ cleaving, sample preparation and characterization chamber: ion sputtering, annealing (300K-1000K), LEED

Additional Tools

Spin- and angle- resolved photoemission spectroscopy endstation available

Environment

UHV

Scanning/Positioning

CARVING manipulator

PSI

Switzerland

ARPES, XPD - PEARL Beamline @ Swiss Light Source Synchrotron

Applications

The PEARL (Photoemission and atomic resolution laboratory) beamline is dedicated to the structural characterisation of local bonding geometry of molecular adsorbates on metal or semiconductor surfaces, of nanostructured surfaces, and of surfaces of complex materials. It is a soft X-ray beamline with an angle-resolved photoelectron spectrometer for angle-scanned and photon energy-scanned X-ray photoelectron diffraction (XPD)

Source

Bending magnet, linear horizontal, partial circular left/right, flux on sample at 1 keV: 2x1011ph/s, spot size: 170μm H x 73μm V, FWHM, 1mm x1mm

Source Energy Range

60 - 2000 eV

Detection

Scienta EW4000 detector

Overall Energy Resolution

Up to 7000 at 400 eV (E/ΔE)

Sample

Temperatures down to 30K, heating to 650 K

Other Capabilities

In-situ sample preparation, cooling-heating, LEED, load-lock

Additional Tools

STM at temperature of 4K

Environment

UHV

Scanning/Positioning

6-axis Carving manipulator

SOLEIL

France

Time resolved photoemission XPS, ARPES, XAS, XMCD - Tempo Beamline @ Soleil Synchrotron

Applications

Time resolution<50ps

SOLEIL

France

XPS, HR-ARPES, Spin-resolved PES - Cassiopee Beamline @ Soleil Synchrotron

Overall Energy Resolution

E/ΔE> 20000

Environment

UHV, MBE chamber

SOLEIL

France

Nano-XPS & ARPES, ARPES - Antares Beamline @ Soleil Synchrotron

Overall Spatial Resolution

<120nm

Uni-NG

Slovenia

CITIUS 2

Applications

Angle resolved Photoemission UPS PES

Source

He discharge lamp (Specs UVS 300)

Source Energy Range

21.2 eV and 40.8 eV

Detection

Scienta R3000 electron energy spectrometer

Overall Energy Resolution

better than 10 meV

Sample

Max sample size 8x8 mm, thickness 2 mm, mounted on flag style sample plates (Mo or Cu). Cryogenic manipulator 5 degrees of freedom (x,y,z, polar angle and tilt), down to 20 K

Other Capabilities

Sample heating stage up to 1000 degrees by electronic bombardment Ar ion sputtering In vacuum cleaver Sample garage

Additional Tools

time resolved ARPES, XPS SEM, TEM Chemical laboratory

Environment

Ultrahigh vacuum

Overall Spatial Resolution

500 micron spot size

Detection Energy Range

(0-1500) eV

Monitors

LEED, microbalance and XPS