Coherent Light-Matter Interactions in Monolayer Transition-Metal Dichalcogenides

• Κύριος συγγραφέας: Sie, Edbert Jarvis (Συγγραφέας, http://id.loc.gov/vocabulary/relators/aut)
• Συγγραφή απο Οργανισμό/Αρχή: SpringerLink (Online service)
• Μορφή: Ηλεκτρονική πηγή Ηλ. βιβλίο
• Γλώσσα: English
• Έκδοση: Cham : Springer International Publishing : Imprint: Springer, 2018.
• Έκδοση: 1st ed. 2018.
• Σειρά: Springer Theses, Recognizing Outstanding Ph.D. Research,
• Θέματα: Surfaces (Physics).; Interfaces (Physical sciences).; Thin films.; Optical materials.; Electronic materials.; Spectroscopy.; Microscopy.; Lasers.; Photonics.; Semiconductors.; Atoms.; Physics.; Surface and Interface Science, Thin Films.; Optical and Electronic Materials.; Spectroscopy and Microscopy.; Optics, Lasers, Photonics, Optical Devices.; Atoms and Molecules in Strong Fields, Laser Matter Interaction.

 This thesis presents optical methods to split the energy levels of electronic valleys in transition-metal dichalcogenides (TMDs) by means of coherent light-matter interactions. The electronic valleys present in monolayer TMDs such as MoS2, WS2, and WSe2 are among the many novel properties exhibited by semiconductors thinned down to a few atomic layers, and have have been proposed as a new way to carry information in next generation devices (so-called valleytronics). These valleys are, however, normally locked in the same energy level, which limits their potential use for applications. The author describes experiment performed with a pump-probe technique using a transient absorption spectroscopy on MoS2 and WS2. It is demonstrated that hybridizing the electronic valleys with light allows one to optically tune their energy levels in a controllable valley-selective manner. In particular, by using off-resonance circularly polarized light at small detuning, one can tune the energy level of one valley through the optical Stark effect. Also presented within are observations, at larger detuning, of a separate contribution from the so-called Bloch--Siegert effect, a delicate phenomenon that has eluded direct observation in solids. The two effects obey opposite selection rules, enabling one to separate the two effects at two different valleys. 

 Chapter1. Introduction -- Chapter2. Time-resolved absorption spectroscopy -- Chapter3. Intervalley biexcitons in monolayer MoS2 -- Chapter4. Valley-selective optical Stark effect in monolayer WS2 -- Chapter5. Intervalley biexcitonic optical Stark effect in monolayer WS2 -- Chapter6. Large, valley-exclusive Bloch--Siegert shift in monolayer WS2 -- Chapter7. Lennard--Jones-like potential of 2D excitons in monolayer WS2 -- Chapter8. WUV based Time-resolved ARPES.