DA30-L Angular Resolved Hemispherical Electron Analyser  | © Scienta Omicron
The DA30-L angular resolved hemispherical analyser with deflector concept.
DA30-L Electron Analyser | © Scienta Omicron
The DA30-L hemispherical analyser comes prepared with a large detector port for integration with our spin transfer system.

DA30-L

First Deflector Analyser Preserving Measurement Geometry

PESARPESHR-ARPESμARPESSpin-ARPESUPS

  • 30° full cone acceptance without sample rotation
  • Spin-resolved MDC without sample rotation
  • Matrix element effects are avoided by keeping sample fixed
  • Ensures same spot for all k//
  • Improved ky accuracy (resolution better than 0.1°)
  • Patented (WO2013/133739)
  • Fast electronic deflection

Besides XPS and UPS, the DA30-L is especially developed for high quality ARPES measurements. Scienta Omicron´s deflector concept enables full cone angular scans in reciprocal space without sample movement. This allows electronic band structure mapping, even spin resolved, of the full surface Brillouin zone without changing measurement geometry, eliminating matrix element effects, and simplifying the interpretation of results dramatically.

With the DA30-L, we presented the world’s first hemispherical analyser using a ground-breaking deflector concept that enables angular scans in two dimensions of k-space without tilting the sample. Since the launch in 2013, the DA30-L has been rapidly accepted by the ARPES community.

Traditional ARPES analysers have an angular mode which is restricted to the angular dispersive θx direction. The detector records a 2D image of intensity for angle θx vs energy E. In such a setup, obtaining full cone measurements requires the sample to be physically rotated to probe the θy angular space. This physical movement can introduce multiple artefacts into the ARPES measurement.

Our analysers overcome these limits by using an internal deflection mode for the θy direction. With this deflection mode, the lens system projects individual slices of θx on to the analyser slit for a given θy angle. Hence, the detector of hemispherical analyser measures slices of θx vs E spectra. Recording these individual slices while changing the θy deflector angle builds a cube of reliable data containing intensity for all θx, θy, and E values.

The deflection mode enables the DA30-L to obtain these full cone measurements with an opening angle of up to ± 15° while avoiding sample rotation, making it an ideal high performance ARPES analyser.

More Information

Deflection Advantage

The deflection feature is a big advantage as it allows to keep the sample in a fixed position and instead uses the deflectors to change the angular range in θy projected on to the analyser slit. This ensures the same position of the sample is probed during the whole measurement. In addition, keeping the experimental geometry fixed throughout the measurement sequence avoids matrix element effects which are caused by variations in ionisation cross section for different photon to sample angles. This allows to acquire higher quality data using the faster and more precise electronic deflection compared with mechanical sample movement. Another advantage, for some samples, is that decreased rotation requirements allow manipulators with fewer degrees of freedom to be used. This ultimately allows for lower sample temperatures to be reached.

DA30-L EXT

The EXT analyser model features an extended energy range to lower kinetic energies. While a regular DA30-L is specified from 3 eV kinetic energy for angular/deflection mode, the EXT type analyser is capable of handling kinetic energies starting from as low as 0.5 eV. Achieving good performance at such low energies puts high demands on the analyser lens mechanics. Other specifications remain the same as for the DA30-L.

DA30-L(W)

The DA30-L(W) includes the wide angular and deflection modes for kinetic energy ranges of lab based UV sources. It is mechanically prepared for the full deflection capabilities of the DA30-L mode, but is delivered without the electronics and software necessary for the high dispersive angular and deflection modes. The electronics and software upgrade is offered separately. The final upgrade to DA30-L can be done at customer site without removing the analyser from the system and without breaking vacuum. The upgrade concerns the computer, software, and high voltage system. Hence, this option presents an easy path to gain future access  to the full DA30-L deflector concept and kinetic energy range.

The DA30-L(W) supports ±7°/±15° in angular mode and ±15° in deflection mode. The upper kinetic energy range in angular as well as deflection mode is limited to 50 eV. 

High Energy Deflection

For experiments that require a higher kinetic energy range in deflection mode an upgrade is available. This upgrade includes electronics and software and extends the kinetic range of the deflection mode up to 800 eV.

Specifications

Energy resolution

< 1.8 meV FWHM

Transmission mode energy range

0.5 eV – 1 500 eV

Angular modes

± 3.5°, ± 7°, ± 15°

Angular mode energy range

3 eV – 1 500 eV

For full specifications and more information about product options, please do not hesitate to contact your local sales representative.

Deflection mode energy range

3 eV – 200 eV

Deflection mode Spin scan

Yes

Operating pressure

< 10-5 mbar

Mounting flange

NW 200 CF

Results

One-Dimensional Confinement and Width-Dependent Bandgap Formation in Epitaxial Graphene Nanoribbons

One-Dimensional Confinement and Width-Dependent Bandgap Formation in Epitaxial Graphene Nanoribbons

2021

The ability to define an off state in logic electronics is the key ingredient that is impossible to fulfill using a conventional pristine graphene layer, due to the absence of an electronic bandgap. For years, this property has been...

Observation of Electrically Tunable van Hove Singularities in Twisted Bilayer Graphene from NanoARPES

Observation of Electrically Tunable van Hove Singularities in Twisted Bilayer Graphene from NanoARPES

2020

The possibility of triggering correlated phenomena by placing a singularity of the density of states near the Fermi energy remains an intriguing avenue toward engineering the properties of quantum materials. Twisted bilayer graphene...

Multiple Topological States in Iron-Based Superconductors

Multiple Topological States in Iron-Based Superconductors

2019

In this work, Peng Zhang & Shik Shin et al. identified topological insulator and Dirac semimetal states near the Fermi energy in different iron-based superconducting compounds. More specifically, they 1) observe that TI bands...

Visualizing Dirac Nodal-Line Band Structure of Topological Semimetal ZrGeSe by ARPES

Visualizing Dirac Nodal-Line Band Structure of Topological Semimetal ZrGeSe by ARPES

2019

As a member of ZrHM (H = Si/Ge/Sn; M = O/S/Se/Te) family materials, which were predicted to be the candidates of topological Dirac nodal-line semimetals, ZrGeSe exhibited particular properties, such as magnetic breakdown effect in...

Reference Systems

Downloads

DA30-L: Angle Resolved Electron Spectrometer

16/04/2021 749.33 KB

Since the launch in 2013, the DA30 family of analysers have revolutionised the field of ARPES. Using a fast electrostatic deflector concept, this well proven analyser can measure electrons in a full cone of 30 degrees opening angle. This opens up for band mapping of the full surface Brillouin zone without the need to rotate the sample and preserves incident and exit angles. The deflection capability ensures fixed spot shape and position on the sample and eliminates mechanical backlash, information depth variations, and angle dependent matrix element effects.

2D/3D Ferrum VLEED Detector for DA30-L

This 2D or 3D spin detection utilizes the exchange scattering mechanisms to be 50x more efficient than Mott schemes. One or two Ferrum VLEED detectors mount on a proprietary transfer lens with high speed switching between channels. The DA30-L's unique deflection mode directs any part of the full acceptance cone to the spin detectors without sample rotation. Integrating the Ferrum and the DA30-L creates the highest quality and most efficient spin ARPES measurements.