Magneto-optics of layered two-dimensional semiconductors and heterostructures: Progress and prospects

Abstract

Beginning with the 'conventional' two-dimensional (2D) quantum wells (QWs) based on III-V and II-VI semiconductors in the 1970s, to the recent atomically-thin sheets of van der Waals materials such as 2D semiconducting transition metal dichalcogenides (TMDCs) and 2D magnets, the research in 2D materials is continuously evolving and providing new challenges. Magnetooptical spectroscopy has played a significant role in this area of research, both from fundamental physics and technological perspectives. A major challenge in 2D semiconductors such as TMDCs is to understand their spin-valley-resolved physics, and their implications in quantum computation and information research. Since the discovery of valley Zeeman effects, deep insights into the spin-valley physics of TMDCs and their heterostructures has emerged through magnetooptical spectroscopy. In this perspective, we highlight the role of magnetooptics in many milestones such as the discovery of interlayer excitons, phase control between coherently-excited valleys, determination of exciton-reduced masses, Bohr radii and binding energies, physics of the optically-bright and dark excitons, trions, other many-body species such as biexcitons and their phonon replicas in TMDC monolayers. The discussion accompanies open questions, challenges and future prospects in the field including comments on the magnetooptics of van der Waals heterostructures involving TMDCs and 2D magnets.

Theoretical study of electronic and optical properties in doped quantum structures with Razavy confining potential: effects of external fields

“…Now, turning to analyzing Fig. 4(d), where a delta-like doping of n d = 4.5 × 10 19 cm −3 combines with an applied magnetic field of 30 T (some experimental and theoretical works in high magnetic fields [75][76][77]), a parabolic confinement appears associated with the second term in the squared parenthesis of Eq. (5).…”

Theoretical Study of Electronic and Optical Properties in Doped Quantum Structures with Razavy Confining Potential: Effects of External Fields

“…Now, turning to analyzing Fig. 4(d), where a delta-like doping of n d = 4.5 × 10 19 cm −3 combines with an applied magnetic field of 30 T (some experimental and theoretical works in high magnetic fields [75][76][77]), a parabolic confinement appears associated with the second term in the squared parenthesis of Eq. (5).…”

Interlayer exciton valley polarization dynamics in large magnetic fields

“…Their band structure leads to spinvalley coupling 4 , and the interband selection rules allow for a coupled spin-valley polarization to be prepared and read out via circularly polarized excitation and helicity-resolved PL 5 . Alternatively, a valley polarization can be induced using external magnetic fields [6][7][8][9] . Combining different TMDC monolayers into van der Waals heterostructures can lead to a type-II band alignment and corresponding charge separation 10,11 .…”