Electron-hole liquid in layered InSe: Comparison of two- and three-dimensional excitonic states

In the paper a theoretical study the both the quantized energies of excitonic states and their wave functions in grapheneand in materials with "Mexican hat" band structure dispersion as well as in zinc-blende GaN is presented. An integral twodimensionalSchrÃ¶dinger equation of the electron-hole pairing for a particles with electron-hole symmetry of reflection isexactly solved. The solutions of SchrÃ¶dinger equation in momentum space in studied materials by projection the twodimensionalspace of momentum on the three-dimensional sphere are found exactly. We analytically solve an integral twodimensionalSchrÃ¶dinger equation of the electron-hole pairing for particles with electron-hole symmetry of reflection. Instudied materials the electron-hole pairing leads to the exciton insulator states. Quantized spectral series and lightabsorption rates of the excitonic states which distribute in valence cone are found exactly. If the electron and hole areseparated, their energy is higher than if they are paired. The particle-hole symmetry of Dirac equation of layered materialsallows perfect pairing between electron Fermi sphere and hole Fermi sphere in the valence cone and conduction cone andhence driving the Cooper instability. The solutions of Coulomb problem of electron-hole pair does not depend from a widthof band gap of graphene. It means the absolute compliance with the cyclic geometry of diagrams at justification of theequation of motion for a microscopic dipole of graphene where >1 s r . The absorption spectrums for the zinc-blendeGaN/(Al,Ga)N quantum well as well as for the zinc-blende bulk GaN are presented. Comparison with availableexperimental data shows good agreement.

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Exciton-polaron Rydberg states in monolayer MoSe2 and WSe2

Nature Communications ◽

10.1038/s41467-021-26304-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Erfu Liu ◽

Jeremiah van Baren ◽

Zhengguang Lu ◽

Takashi Taniguchi ◽

Kenji Watanabe ◽

...

Keyword(s):

Boron Nitride ◽

Excited States ◽

Ground State ◽

Transition Metal Dichalcogenides ◽

Rydberg States ◽

Energy Shift ◽

Many Body ◽

Electron Hole ◽

Metal Dichalcogenides ◽

Excitonic States

AbstractExciton polaron is a hypothetical many-body quasiparticle that involves an exciton dressed with a polarized electron-hole cloud in the Fermi sea. It has been evoked to explain the excitonic spectra of charged monolayer transition metal dichalcogenides, but the studies were limited to the ground state. Here we measure the reflection and photoluminescence of monolayer MoSe2 and WSe2 gating devices encapsulated by boron nitride. We observe gate-tunable exciton polarons associated with the 1 s–3 s exciton Rydberg states. The ground and excited exciton polarons exhibit comparable energy redshift (15~30 meV) from their respective bare excitons. The robust excited states contradict the trion picture because the trions are expected to dissociate in the excited states. When the Fermi sea expands, we observe increasingly severe suppression and steep energy shift from low to high exciton-polaron Rydberg states. Their gate-dependent energy shifts go beyond the trion description but match our exciton-polaron theory. Our experiment and theory demonstrate the exciton-polaron nature of both the ground and excited excitonic states in charged monolayer MoSe2 and WSe2.

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Long-distance coupling and energy transfer between exciton states in magnetically controlled microcavities

Communications Materials ◽

10.1038/s43246-020-00079-x ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Maciej Ściesiek ◽

Krzysztof Sawicki ◽

Wojciech Pacuski ◽

Kamil Sobczak ◽

Tomasz Kazimierczuk ◽

...

Keyword(s):

Energy Transfer ◽

Quantum Wells ◽

Long Distance ◽

Electron Hole ◽

Quantum Networks ◽

Spatial Direction ◽

Optical Microcavities ◽

Excitonic States ◽

The Magnetic Field ◽

Quantum Emitters

Abstract Coupling of quantum emitters in a semiconductor relies, generally, on short-range dipole-dipole or electronic exchange type interactions. Consistently, energy transfer between exciton states, that is, electron-hole pairs bound by Coulomb interaction, is limited to distances of the order of 10 nm. Here, we demonstrate polariton-mediated coupling and energy transfer between excitonic states over a distance exceeding 2 μm. We accomplish this by coupling quantum well-confined excitons through the delocalized mode of two coupled optical microcavities. Use of magnetically doped quantum wells enables us to tune the confined exciton energy by the magnetic field and in this way to control the spatial direction of the transfer. Such controlled, long-distance interaction between coherently coupled quantum emitters opens possibilities of a scalable implementation of quantum networks and quantum simulators based on solid-state, multi-cavity systems.

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Symmetry selected quantum dynamics of few electrons in nanopillar transistors

Scientific Reports ◽

10.1038/s41598-019-56256-7 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Yue-Min Wan ◽

Heng-Tien Lin

Keyword(s):

Quantum Number ◽

Quantum Dynamics ◽

Three Dimensional ◽

Single Electron ◽

Electron Hole ◽

Current Voltage ◽

Weak Symmetry ◽

Current Voltage Characteristics ◽

The One

AbstractStudy on single electron tunnel using current-voltage characteristics in nanopillar transistors at 298 K show that the mapping between the Nth electron excited in the central box ∼8.5 × 8.5 × 3 nm3 and the Nth tunnel peak is not in the one-to-one correspondence to suggest that the total number N of electrons is not the best quantum number for characterizing the quality of single electron tunnel in a three-dimensional quantum box transistor. Instead, we find that the best number is the sub-quantum number nz of the conduction z channel. When the number of electrons in nz is charged to be even and the number of electrons excited in the nx and ny are also even at two, the adding of the third electron into the easy nx/ny channels creates a weak symmetry breaking in the parity conserved x-y plane to assist the indirect tunnel of electrons. A comprehensive model that incorporates the interactions of electron-electron, spin-spin, electron-phonon, and electron-hole is proposed to explain how the excited even electrons can be stabilized in the electric-field driving channel. Quantum selection rules with hierarchy for the ni (i = x, y, z) and N = Σni are tabulated to prove the superiority of nz over N.

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Dimensionality dependence of the band-gap renormalization in two- and three-dimensional electron-hole plasmas in GaAs

Physical Review Letters ◽

10.1103/physrevlett.58.419 ◽

1987 ◽

Vol 58 (4) ◽

pp. 419-422 ◽

Cited By ~ 225

Author(s):

G. Tränkle ◽

H. Leier ◽

A. Forchel ◽

H. Haug ◽

C. Ell ◽

...

Keyword(s):

Band Gap ◽

Three Dimensional ◽

Dimensional Electron ◽

Electron Hole

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LOCALIZATION EFFECTS IN SEMICONDUCTOR SUPERLATTICES

Journal of Nonlinear Optical Physics & Materials ◽

10.1142/s0218863596000052 ◽

1996 ◽

Vol 05 (01) ◽

pp. 33-50

Author(s):

S.J. LEE ◽

J.B. KHURGIN

Keyword(s):

Electric Field ◽

Oscillator Strength ◽

Optical Field ◽

Carrier Localization ◽

Semiconductor Superlattices ◽

Electron Hole ◽

Single Quantum Well ◽

Optical Detector ◽

Dc Electric Field ◽

Excitonic States

We investigated two novel effects utilizing localization properties of semiconductor super-lattices. First, a phenomenon which consists of optically induced effective mass change due to carrier localization in semiconductor superlattices is investigated. It is shown that an optical field can achieve conductivity changes in a manner similar to a dc electric field. A possible application as a nonabsorbing differential optical detector/switch is considered. Second, radiative recombination of the excitonic states in semiconductor superlattices with an applied electric field is studied theoretically. It is shown that when the electron-hole Coulomb interaction energy exceeds the miniband width, a coherent excitonic state is created whose oscillator strength surpasses the oscillator strength of a single quantum well by orders of magnitude. It is also demonstrated that a small external field can split the coherent state into isolated well states and thus severely deplete the oscillator strength of the exciton. This opens the possibility of modulating and switching of superradiance in semiconductor devices.

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