Instytut Podstawowych Problemów Techniki

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The Coulomb-driven renormalization of electronic compressibility in monolayer MoS2 remains poorly understood at finite temperatures. Using the Rytova–Keldysh potential with a nonlocal dielectric response, we calculate the compressibility as a function of carrier density and temperature in experimentally relevant regimes. The exchange and correlation energies are treated, respectively, within the noninteracting (NI), Hartree–Fock (HF), and random phase approximation (RPA) frameworks. We demonstrate that the RPA, through enhanced screening induced by many-body correlations, yields negative values of the electronic compressibility,
in agreement with recent measurements resolved in temperature and density. At high temperatures (

Słowa kluczowe:

Graphene, Quantum well, TMDCs, Compressibility TMDCs, Capacity quantum

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Streszczenie:

We theoretically investigate electron-electron interaction effects on the single-particle Green's function of doped monolayer MoS2, employing a massless Dirac continuum model within the random phase approximation and incorporating long-range Coulomb interactions via a modified Keldysh potential. Our calculations provide quantitative predictions for the many-body spectral function, the renormalized quasiparticle energy dispersion, and the renormalized velocity at both zero and finite temperatures, taking into account carrier density, electric field intensity, and spin polarization. We identify experimentally detectable many-body signatures that are substantially enhanced with decreasing carrier density, electric field, and spin polarization, alongside intriguing instabilities in the excitation spectrum at small wave vectors where interactions completely destroy the noninteracting linear dispersion. The velocity renormalization exhibits a leading-order temperature correction that is linear and positive, with a universal, density-independent slope in the high-density limit. We further predict an enhanced effective velocity at low temperatures and a nonmonotonic temperature dependence at higher temperatures (e.g.

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Coulomb-driven renormalization of electronic spectra in monolayer transition-metal dichalcogenides (TMDCs) remains poorly understood at finite temperature. Using the Rytova-Keldysh potential with a non-local dielectric response, we calculate quasiparticle band-gap renormalization (BGR) and the Fermi-edge absorption spectrum over experimentally relevant carrier densities and temperatures. Exchange and correlation self-energies are treated successively within Hartree-Fock (HF), the random-phase approximation (RPA), and the Hubbard local-field approximation (HFA). Only the HFA, which embeds the G(q) local-field factor, reproduces recent temperature- and densityresolved measurements: it broadens the band gap at low densities and produces a density-induced redshift of the Fermi absorption edge through enhanced screening. The same framework accounts for the nonmonotonic BGR observed in cyclotron resonance experiments on disordered monolayers when disorder-induced thermal broadening is included. The results establish a local-field-corrected many-body theory as the minimal quantitative description of carrier-doped TMDCs and provide a roadmap for engineering interaction-driven electronic phases in two dimensions.

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The electronic properties of monolayer two-dimensional are strongly influenced by the presence of a perpendicular electric field (), finite temperature (), an externally applied spin-polarized exchange field (), and spin-valley coupling effects () induced by surface adatoms or magnetic proximity interactions with a ferromagnetic substrate. Within the framework of the Random Phase Approximation (RPA), we investigate how these external fields reshape electron–electron interactions and provide both analytical and numerical results for the density of states (DOS), quantum capacitance, and effective Fermi velocity. Our findings show that the interplay between , , and leads to the emergence of a spin-valley coupling dependent self-energy structure in the charge carriers, resulting in pronounced spin- and valley-polarized behavior of the effective Fermi velocity. Our predictions agree well with available experimental data and reveal that the Fermi velocity can be tuned via spin polarization, enriching the qualitative and quantitative understanding of quantum effects in these materials.

Słowa kluczowe:

ffective velocity Fermi,Quantum capacity,Dos,Quantum well,TMDC

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