Camel's back excitons in GaP

Altarelli, M.; Sabatini, Riccardo; Lipari, N. O.

doi:10.1016/0038-1098(78)90917-1

Cited by 30 publications

(2 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1b , the electron accelerates in the same direction as the hole. It is important to stress that, because the HX forms around the K -point, such an exciton is not related to the so-called “camel’s back exciton” formed due to a local camel-back-like structure in the conduction band 42 , or the somewhat more controversial so-called “bielectron” state 43 – 45 . In this proposed bound bielectron model, a negative-mass electron and a positive-mass electron from different conduction bands are bound together under the condition of the negative-mass electron being lighter.…”

Section: Discussionmentioning

confidence: 99%

Narrow-band high-lying excitons with negative-mass electrons in monolayer WSe2

et al. 2021

View full text Add to dashboard Cite

Monolayer transition-metal dichalcogenides (TMDCs) show a wealth of exciton physics. Here, we report the existence of a new excitonic species, the high-lying exciton (HX), in single-layer WSe2 with an energy of ~3.4 eV, almost twice the band-edge A-exciton energy, with a linewidth as narrow as 5.8 meV. The HX is populated through momentum-selective optical excitation in the K-valleys and is identified in upconverted photoluminescence (UPL) in the UV spectral region. Strong electron-phonon coupling results in a cascaded phonon progression with equidistant peaks in the luminescence spectrum, resolvable to ninth order. Ab initio GW-BSE calculations with full electron-hole correlations explain HX formation and unmask the admixture of upper conduction-band states to this complex many-body excitation. These calculations suggest that the HX is comprised of electrons of negative mass. The coincidence of such high-lying excitonic species at around twice the energy of band-edge excitons rationalizes the excitonic quantum-interference phenomenon recently discovered in optical second-harmonic generation (SHG) and explains the efficient Auger-like annihilation of band-edge excitons.

show abstract

Section: Discussionmentioning

confidence: 99%

Narrow-band high-lying excitons with negative-mass electrons in monolayer WSe2

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The consideration of the exact conduction band structure requires an extension of the theory developed in [3] which was beyond the scope of the present paper. This affects some of the exciton parameters as shown by [15].…”

Section: (O)mentioning

confidence: 98%

On the quantitative characterization of chemical disorder of In_1−xGa_xP from wavelength‐modulated No‐phonon absorption

Strehlow¹,

Kuhn²,

Friedrich³

et al. 1978

Physica Status Solidi (b)

View full text Add to dashboard Cite

Wavelength-modulated transmission spectra of the no-phonon structure of In1 -%Ga,P are quantitatively analysed on the basis of a recently developed theory. From this comparison the Koster-Slater parameter J characterizing the magnitude of chemical disorder is determined. The theory also well accounts for the experimentally observed lineshape of the no-ph6non structure. From the intensity ratio of the no-phonon and LA-phonon-assisted transitions the quantity JJC is estimated where C is the deformation potential constant for lattice deformation by LA phonons.Es werden Wellenliingen-modulierte Transmissions-Spektren der Null-Phonon-Struktur von In1 -,Ga,P auf der Grundlage einer kiirzlich entwickelten Theorie analysiert. Aus diesem Vergleich wird der die chemische Unordnung charakterisierende Koster-Slater-Parameter J bestimmt. Auch die experimentell beobachtete Linienform der Null-Phonon-Struktur wird von der Theorie gut wiedergegeben. Aus dem Intensitiitsverhaltnis des Null-Phonon-und des LA-Phonon-Vbergangs wird die GroBe J/C ermittelt, wobei C die Deformationspotential-Konstante fiir Gitterdeformation durch LA-Phononen ist.

show abstract

Excitons and Electron–Hole Liquid State in 2D γ‐Phase Group‐IV Monochalcogenides

Luo

Duan

Yakobson

et al. 2020

Adv Funct Materials

View full text Add to dashboard Cite

Different dispersion near the electronic band edge of a semiconductor can have great influence on its transport, thermoelectric, and optical properties. Using first-principles calculations, it is demonstrated that a new phase of group-IV monochalcogenides (γ-MX, M = Ge, Sn; X = S, Se, or Te) can be stabilized in monolayer limit. γ-MXs are shown to possess a unique band dispersion-that is, camel's back like structure-in the top valence band. The band nesting effect near the camel's back region induces a large excitonic absorbance and significantly different exciton behaviors from other 2D materials. Importantly, the small effective mass and the indirect characteristics of lowest-energy exciton render it advantageous for the generation of electron-hole liquid state. After careful evaluation of the electron-hole dissociation temperature and the Mott critical density, it is predicted that a high-temperature exciton gas to electron-hole liquid phase transition can be achieved in these materials with a low excitation power density. The findings open up new opportunities for both the fundamental research on exciton physics and design of excitonic devices based on 2D materials with distinct band dispersion.

show abstract

Camel's back excitons in GaP

Cited by 30 publications

References 12 publications

Narrow-band high-lying excitons with negative-mass electrons in monolayer WSe2

Narrow-band high-lying excitons with negative-mass electrons in monolayer WSe2

On the quantitative characterization of chemical disorder of In_1−xGa_xP from wavelength‐modulated No‐phonon absorption

Excitons and Electron–Hole Liquid State in 2D γ‐Phase Group‐IV Monochalcogenides

Contact Info

Product

Resources

About

Camel's back excitons in GaP

Cited by 30 publications

References 12 publications

Narrow-band high-lying excitons with negative-mass electrons in monolayer WSe2

Narrow-band high-lying excitons with negative-mass electrons in monolayer WSe2

On the quantitative characterization of chemical disorder of In1−xGaxP from wavelength‐modulated No‐phonon absorption

Excitons and Electron–Hole Liquid State in 2D γ‐Phase Group‐IV Monochalcogenides

Contact Info

Product

Resources

About

On the quantitative characterization of chemical disorder of In_1−xGa_xP from wavelength‐modulated No‐phonon absorption