High-Precision Spin-Resolved Electronic Structures of Si(110)-"16x2" chiral surfaces
Lead Research Organisation:
University of Manchester
Department Name: Physics and Astronomy
Abstract
This proposal is for travel and subsistence funds to enable Prof. Seddon (the PI) and a post-graduate student to carry out experimental work (for which beamtime has recently been awarded) on the APE-LE photoemission station at the Elettra synchrotron (Italy). Travel, accommodation and subsistence for work at Elettra used to be provided under the Calipso Transnational Access program, which unfortunately is no longer available.
In this beamtime we aim to perform accurate, high-precision electron spin polarisation measurements for Si(110)-"16x2" surfaces that our calculations have predicted will exhibit small polarisations due to the surface chirality. The proposed experimental programme has been advanced, compared with previous experimental work at Elettra, in order to ensure the generation of unequivocal data. Results indicating that the two enantiomeric surfaces exhibit spin polarisations that 'mirror' each other would be a robust result that would have a significant impact in the field of spintronics as it raises the possibility that polarised electrons could be injected into silicon based electronics components without the need for magnetic overlayers etc.
This work is a key part of our on-going project exploring manifestations of chirality and the Rashba effect in semiconductor materials with a particular focus on spin injection/detection.
In this beamtime we aim to perform accurate, high-precision electron spin polarisation measurements for Si(110)-"16x2" surfaces that our calculations have predicted will exhibit small polarisations due to the surface chirality. The proposed experimental programme has been advanced, compared with previous experimental work at Elettra, in order to ensure the generation of unequivocal data. Results indicating that the two enantiomeric surfaces exhibit spin polarisations that 'mirror' each other would be a robust result that would have a significant impact in the field of spintronics as it raises the possibility that polarised electrons could be injected into silicon based electronics components without the need for magnetic overlayers etc.
This work is a key part of our on-going project exploring manifestations of chirality and the Rashba effect in semiconductor materials with a particular focus on spin injection/detection.
Planned Impact
Recently reported, chirally-induced, spin selectivity has involved large chiral adsorbate molecules and spin filtering. Whilst this approach has produced interesting results, an approach more directly relevant to technological applications would be a system based purely on Si, which is the most widely used semiconductor material, and would involve direct generation of polarised electrons i.e. circumventing the need for both a complex chiral organic ad-layer and spin filtering.
In the forthcoming beamtime we aim to perform accurate, high-precision electron spin polarisation measurements for Si(110)-"16x2" surfaces that our calculations have predicted will exhibit small polarisations due to the surface chirality. This work is a key part of our on-going project exploring manifestations of chirality and the Rashba effect in semiconductor materials with a particular focus on spin injection/detection.
Results indicating that the two enantiomeric surfaces exhibit spin polarisations that 'mirror' each other would be a robust result that would have a significant impact in the field of spintronics as it raises the possibility that polarised electrons can be injected into silicon based electronics components without the need for magnetic overlayers etc.
In the forthcoming beamtime we aim to perform accurate, high-precision electron spin polarisation measurements for Si(110)-"16x2" surfaces that our calculations have predicted will exhibit small polarisations due to the surface chirality. This work is a key part of our on-going project exploring manifestations of chirality and the Rashba effect in semiconductor materials with a particular focus on spin injection/detection.
Results indicating that the two enantiomeric surfaces exhibit spin polarisations that 'mirror' each other would be a robust result that would have a significant impact in the field of spintronics as it raises the possibility that polarised electrons can be injected into silicon based electronics components without the need for magnetic overlayers etc.
People |
ORCID iD |
| Elaine Seddon (Principal Investigator) |
Publications
Lewis N
(2019)
Spin- and angle-resolved photoemission studies of the electronic structure of Si(110)" 16 × 2 " surfaces
in Physical Review B
| Description | We determined the electronic structure of a complex chiral reconstruction of the surface of silicon, Si(110)"16x2" at low temperature (77K). This work revealed a number of electronic states concentrated at the surface which were all consistent the Adatom-Buckling model of the surface. In addition we performed an experiment to determine whether or not a 'workable' number of polarised electrons were emitted on illumination of a chiral surface of silicon with soft X-ray radiation. If so use of this system would have had a large impact on the field of spintronics. In the event we found that the polarised emission was very small - of the order of a 3 percent. As such it is not viable for device applications. |
| Exploitation Route | We will take this work forward by looking at the polarisation of electrons emitted from chiral surfaces of elements such as tungsten for which the underlying effects will be much stronger. |
| Sectors | Electronics |
| Description | Anglo, French, US chiral surfaces collaboration |
| Organisation | Ecole Polytechnique |
| Country | France |
| Sector | Academic/University |
| PI Contribution | Original project ideas Beamtime applications and team organisation Sample purchases Sample preparation prior to beamtime |
| Collaborator Contribution | Intellectual and technical input Cost of return flights between Paris and Trieste, hotel and food (10 days) for two team members Cost of return flights between Lincoln Nebraska and Trieste, hotel and food (10 days) for one team member |
| Impact | Not multidisciplinary. Other outputs? |
| Description | Anglo, French, US chiral surfaces collaboration |
| Organisation | University of Nebraska-Lincoln |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Original project ideas Beamtime applications and team organisation Sample purchases Sample preparation prior to beamtime |
| Collaborator Contribution | Intellectual and technical input Cost of return flights between Paris and Trieste, hotel and food (10 days) for two team members Cost of return flights between Lincoln Nebraska and Trieste, hotel and food (10 days) for one team member |
| Impact | Not multidisciplinary. Other outputs? |
| Description | NL Seminar |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Group seminar at the Ecole Polytechnique Paris. A Cockcroft Institute Seminar at Daresbury Laboratory Seminar at Manchester University |
| Year(s) Of Engagement Activity | 2019 |