Spin-Orbit Coupling in Functionalized Graphene

Item type:	Thesis of the University of Regensburg (PhD)
Open Access Type:	Primary Publication
Date:	27 August 2021
Referee:	PD Dr. Jonathan Eroms
Date of exam:	6 June 2021
Institutions:	Physics > Institute of Experimental and Applied Physics > Chair Professor Weiss > Group Dieter Weiss
Keywords:	Graphene, spin-orbit coupling, spintronics
Dewey Decimal Classification:	500 Science > 530 Physics
Status:	Published
Refereed:	Yes, this version has been refereed
Created at the University of Regensburg:	Yes
Item ID:	46409

Abstract (English)

Due to its high room temperature electron mobility and long spin diffusion length, the two-dimensional material graphene is a promising material for possible spintronic applications. Here, the electron spin of an electron is used as a degree of freedom, additionally to its charge, to transport information. However, the small spin-orbit coupling(SOC)-strength in pristine graphene prevents ...

Abstract (English)

Due to its high room temperature electron mobility and long spin diffusion length, the two-dimensional material graphene is a promising material for possible spintronic applications. Here, the electron spin of an electron is used as a degree of freedom, additionally to its charge, to transport information. However, the small spin-orbit coupling(SOC)-strength in pristine graphene prevents functionalities such as the manipulation of the electron spin direction by electronic gates or the generation of spin currents through charge to spin conversion effects, which are essential for many possible applications.
The thesis therefore explores two methods to drastically enhance the SOC in graphene by functionalization. First, a dilute amount of hydrogen was applied by exposing graphene to a hydrogen plasma. Here, the hydrogen atoms form covalent bonds with the carbon atoms in graphene. The corresponding mixing of electronic states from different bands is thus expected to increase the SOC in graphene. Second, graphene was placed into direct contact with the two-dimensional semiconductor WSe2. In these heterostructures, the large SOC of the WSe2 is imprinted in the adjacent graphene by hybridization of the electronic states of the two materials.
Signatures of the induced SOC in the fabricated devices are then examined by a number of charge and spin transport measurement methods. These include electrical spin injection, investigation of the spin-Hall effect, as well as the weak localization/antilocalization effect. Further, the charge transport characteristics of the fabricated devices and the possibility to tune the induced SOC by electronic gates are studied.

Translation of the abstract (German)

Die geringe Spin-Bahn Kopplung in Graphen schränkt mögliche Anwendungen in der Spintronik ein. Deshalb werden zwei unterschiedliche Methoden untersucht diese Spin-Bahn Kopplung durch Funktionalisierung zu erhöhen. Kontrolliertes Anbringen von Wasserstoffatomen führt zu einer Mischung der elektronischen Zustände in Graphen, wodurch eine lokale Erhöhung der Spin-Bahn Kopplung erwartet wird. ...

Translation of the abstract (German)

Die geringe Spin-Bahn Kopplung in Graphen schränkt mögliche Anwendungen in der Spintronik ein. Deshalb werden zwei unterschiedliche Methoden untersucht diese Spin-Bahn Kopplung durch Funktionalisierung zu erhöhen.
Kontrolliertes Anbringen von Wasserstoffatomen führt zu einer Mischung der elektronischen Zustände in Graphen, wodurch eine lokale Erhöhung der Spin-Bahn Kopplung erwartet wird. Ausserdem wurde Graphen in Kontakt mit dem zweidimensionalen Halbleiter WSe2 gebracht, wodurch ein Teil der hohen Spin-Bahn Kopplung von WSe2 auf das Graphen übertragen wird.
Die entsprechenden Proben wurden dann mit Ladungs- und Spintransportexperimenten auf die erhöhte Spin-Bahn Kopplung untersucht.

Linked items

Details

Preview

Export bibliographical data

Abstract (English)

Abstract (English)

Translation of the abstract (German)

Translation of the abstract (German)

Download Statistics

Downloads

More literature (via CORE)

University Library