By performing ab initio calculations for one- to four-layer black phosphorus within the GW approximation, we obtain a significant difference in the band gap (~1.5 eV), which is in line with recent ...experimental data. The results are analyzed in terms of the constructed four-band tight-binding model, which gives accurate descriptions of the mono- and bilayer band structure near the band gap, and reveal an important role of the interlayer hoppings, which are largely responsible for the obtained gap difference.
We present a theory for single- and two-phonon charge carrier scattering in anisotropic two-dimensional semiconductors applied to single-layer black phosphorus (BP). We show that in contrast to ...graphene, where two-phonon processes due to the scattering by flexural phonons dominate at any practically relevant temperatures and are independent of the carrier concentration n, two-phonon scattering in BP is less important and can be considered negligible at n≳10^{13} cm^{-2}. At smaller n, however, phonons enter in the essentially anharmonic regime. Compared to the hole mobility, which does not exhibit strong anisotropy between the principal directions of BP (μ_{xx}/μ_{yy}∼1.4 at n=10^{13} cm^{-2} and T=300 K), the electron mobility is found to be significantly more anisotropic (μ_{xx}/μ_{yy}∼6.2). Absolute values of μ_{xx} do not exceed 250 (700) cm^{2} V^{-1} s^{-1} for holes (electrons), which can be considered as an upper limit for the mobility in BP at room temperature.
•Chemically reduced graphene oxide paper has fairly high irradiation stability.•The electrical conductivity varies nonmonotonically with increasing radiation dose.•Changes in electrical conductivity ...caused by irradiation are more substantial at low temperature.•In a wide temperature range, the electrical conductivity mechanism is a variable range hopping.•Electron beam irradiation does not change the electrical conductivity mechanism.
Effect of 1 MeV electron irradiation with the dose up to 160 × 1015 cm−2 on the electrical properties of reduced graphene oxide paper (rGOP) was investigated in a temperature range of 8–300 K. It was found that rGOP has fairly high irradiation stability, but sufficiently high dose causes nonmonotonic changes in the resistivity. The effect of electron irradiation on the resistivity is more substantial under the low temperatures of electrical measurements. It was assumed that the modification of electrical properties is due to the effect of electron irradiation on the ensembles of the sp3-hybridized carbon atoms. It was shown that in the studied rGOP, the transport of charge carriers occurs by variable range hopping conductivity in the wide temperature range and conduction mechanism remains the same after electron irradiation.
We provide a tight-binding model parametrization for black phosphorus (BP) with an arbitrary number of layers. The model is derived from partially self-consistent GW sub(0) approach, where the ...screened Coulomb interaction W sub(0) is calculated within the random phase approximation on the basis of density functional theory. We thoroughly validate the model by performing a series of benchmark calculations, and determine the limits of its applicability. The application of the model to the calculations of electronic and optical properties of multilayer BP demonstrates good quantitative agreement with ab initio results in a wide energy range. We also show that the proposed model can be easily extended for the case of external fields, yielding the results consistent with those obtained from first principles. The model is expected to be suitable for a variety of realistic problems related to the electronic properties of multilayer BP including different kinds of disorder, external fields, and many-body effects.
Electron correlation effects are studied in ZrSiS using a combination of first-principles and model approaches. We show that basic electronic properties of ZrSiS can be described within a ...two-dimensional lattice model of two nested square lattices. A high degree of electron-hole symmetry characteristic for ZrSiS is one of the key features of this model. Having determined model parameters from first-principles calculations, we then explicitly take electron-electron interactions into account and show that, at moderately low temperatures, ZrSiS exhibits excitonic instability, leading to the formation of a pseudogap in the electronic spectrum. The results can be understood in terms of Coulomb-interaction-assisted pairing of electrons and holes reminiscent of that of an excitonic insulator. Our finding allows us to provide a physical interpretation of the unusual mass enhancement of charge carriers in ZrSiS recently observed experimentally.
The width of the f1(1285)→e+e− decay is calculated in the vector meson dominance model. The result depends on the relative phase between two coupling constants describing f1→ρ0γ decay. The width ...Γ(f1→e+e−) is estimated to be ≃0.07–0.19 eV. Direct f1 production in e+e− collisions is discussed, and the e+e−→f1→a0π→ηππ cross section is calculated. Charge asymmetry in the e+e−→ηπ+π− reaction due to interference between e+e−→f1 and e+e−→ηρ0 amplitudes is studied.
Parameterization of the form factors of f1(1285) meson is proposed. This parameterization is consistent with the available experimental data on the cross sections of f1(1285) meson production in the ...processes e+e−→f1(1285) and e+e−→e+e−f1(1285), as well as on the widths of the decays f1(1285)→e+e−, f1(1285)→ρ0γ, f1(1285)→ρ0π+π−, and f1(1285)→2π+2π−. Our parameterization is also consistent with the predictions for the asymptotic behavior of these form factors.
We show that hole states in recently discovered single-layer InSe are strongly renormalized by the coupling with acoustic phonons. The coupling is enhanced significantly at moderate hole doping ...(∼1013 cm−2) due to hexagonal warping of the Fermi surface. While the system remains dynamically stable, its electron-phonon spectral function exhibits sharp low-energy resonances, leading to the formation of satellite quasiparticle states near the Fermi energy. Such many-body renormalization is predicted to have two important consequences. First, it significantly suppresses charge carrier mobility reaching ∼1 cm2 V−1 s−1 at 100 K in a freestanding sample. Second, it gives rise to unusual temperature-dependent optical excitations in the midinfrared region. Relatively small charge carrier concentrations and realistic temperatures suggest that these excitations may be observed experimentally.
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