arXiv subjects

Mohammad Alidoosti

Publications and source records attributed to Mohammad Alidoosti.

4 recordsLinked to original sources

arXiv2022

Superconducting properties of doped blue phosphorene: Effects of non-adiabatic approach

We study the effects of Kohn anomalies on the superconducting properties in electron- and hole-doped cases of monolayer blue phosphorene, considering both adiabatic and non-adiabatic phonon dispersions using first-principles calculations. We show that the topology of the Fermi surface is crucial for the formation of Kohn anomalies of doped blue phosphorene. By using the anisotropic Eliashberg formalism, we further carefully consider the temperature dependence of the non-adiabatic phonon dispersions. In cases of low hole densities, strong electron-phonon coupling leads to a maximum critical temperature of $T_c=97$ K for superconductivity. In electron-doped regimes, on the other hand, a maximum superconducting critical temperature of $T_c=38$ K is reached at a doping level that includes a Lifshitz transition point. Furthermore, our results indicate that the most prominent component of electron-phonon coupling arises from the coupling between an in-plane (out-of-plane) deformation and in-plane (out-of-plane) electronic states of the electron (hole) type doping.

cond-mat.supr-con↗

arXiv2022

$σ_h$ symmetry and electron-phonon interaction in two-dimensional crystalline systems

The coupling of electrons and phonons is governed wisely by the symmetry properties of the crystal structures. In particular, for two-dimensional (2D) systems, it has been suggested that the electrons do not couple to phonons with pure out-of-plane distortion, as long as there is a $σ_h$ symmetry. We show that such a statement is correct when constituents of the unit-cell layer are only located in the $σ_h$ symmetric plane; a prominent example of such a system is graphene. For those 2D crystals in which atoms are vertically located away from the horizontal symmetric plane (e.g., 1H transition metal dichalcogenides), acoustic flexural modes do not couple to the electrons up to linear order, while optical flexural phonons, which preserve $σ_h$ symmetry, do couple with the electrons. Our conclusions are supported by an analytic argument together with numerical calculations using density functional perturbation theory.

cond-mat.mes-hall↗

arXiv2021

Charge density wave and superconducting phase in monolayer InSe

In this paper, the completed investigation of a possible superconducting phase in monolayer indium selenide is determined using first-principles calculations for both the hole and electron doping systems. The hole-doped dependence of the Fermi surface is exclusively fundamental for monolayer InSe. It leads to the extensive modification of the Fermi surface from six separated pockets to two pockets by increasing the hole densities. For low hole doping levels of the system, below the Lifshitz transition point, superconductive critical temperatures $T_c \sim 55-75$ K are obtained within anisotropic Eliashberg theory depending on varying amounts of the Coulomb potential from 0.2 to 0.1. However, for some hole doping above the Lifshitz transition point, the combination of the temperature dependence of the bare susceptibility and the strong electron-phonon interaction gives rise to a charge density wave that emerged at a temperature far above the corresponding $T_c$. Having included non-adiabatic effects, we could carefully analyze conditions for which either a superconductive or charge density wave phase occurs in the system. In addition, monolayer InSe becomes dynamically stable by including non-adiabatic effects for different carrier concentrations at room temperature.

cond-mat.mtrl-sci↗

arXiv2020

Low-loss two-dimensional plasmon modes in antimonene

The effects of spin-orbit (SOC) and electron-phonon coupling on the collective excitation of doped monolayer Sb$_2$ are investigated using density functional and many-body perturbation theories. The spin-orbit coupling is exclusively important for the monolayer Sb$_2$ and it leads to the reconstruction of the electronic band structure. In particular, plasmon modes of monolayer Sb$_2$ are quite sensitive to the SOC and are characterized by very low damping rates owing to small electron-phonon scatterings. Our results show plasmons in antimonene are significantly less damped compared to monolayer graphene when plasmon energies are $\hbar ω> 0.2$ eV due to smaller plasmon-phonon coupling in the former material.

cond-mat.mtrl-sci↗