Palestrante: Dr. Paulo Eduardo Faria Júnior (University of Regensburg, Germany)

 

Resumo:

 

Van der Waals (vdW) layered materials have emerged as a novel platform

for investigating fundamental questions of quantum many-body phenomena in reduced

dimensions. Among the diverse vdW compounds, transition metal dichalcogenides (TMDCs) are

rather relevant for hosting robust many-body optical excitations, known as excitons.

This colloquium will discuss how the interplay between the spin and orbital angular

momenta of electrons, holes, and excitons can be used as a powerful ''imaging

tool'' to reveal important signatures of elusive many-body phenomena in van der Waals

materials and heterostructures. These emerging physical phenomena are particularly

relevant for uncovering fundamental insights in many-body physics within the

domains of valleytronics, straintronics, and twistronics. Furthermore, this

fundamental understanding can boost novel optoelectronic and optospintronic

applications, while also providing a promising avenue for developments in the field of

quantum information technology.

 

Specifically, I will cover the basic physics behind spin and orbital angular momenta,

encoded in the effective g-factors, emphasizing recent first-principles developments

in pristine monolayer TMDCs[1], which provide a robust theoretical framework to

unveil: (i) the phonon-mediated exciton hybridization in strained WS2 systems[2,3],

(ii) the valley Zeeman splitting of dipolar excitons in MoSe2/WSe2 under external

electric fields[4], and (iii) the proximity-enhanced valley Zeeman splitting in

WS2/graphene systems[5].

 

 

 

[1] Woźniak, Faria Junior et al., Phys. Rev. B (Editors' Suggestion) 101, 235408 (2020).

[2] Faria Junior et al., New J. Phys. 24, 083004 (2022).

[3] Blundo, Faria Junior et al., Phys. Rev. Lett. 129, 067402 (2022).

[4] Faria Junior, Fabian, Nanomaterials 13, 1187 (2023).

[5] Faria Junior et al., 2D Mater. 10, 03400 (2023).