Electron-phonon properties, structural stability, and superconductivity of doped antimonene

Abstract

Antimonene is a recently discovered two-dimensional semiconductor with exceptional environmental stability, high carrier mobility, and strong spin-orbit interactions. In combination with electric field, the latter provides an additional degree of control over the material's properties because of induced spin splitting. Here, we report on a computational study of electron-phonon coupling and superconductivity in n-and p-doped antimonene, where we pay a special attention on the effect of the perpendicular electric field. The range of accessible hole concentrations is significantly limited by the dynamical instability, associated with strong Fermi-surface nesting. At the same time, we find that in the case of electron-doping antimonene remains stable and can be turned into a state with strong electron-phonon coupling, with the mass enhancement factor λ of up to 2.3 at realistic charge carrier concentrations. In this regime, antimonene is expected to be a superconductor with the critical temperature of ≈16 K. Application of bias voltage leads to a considerable modification of the electronic structure, affecting the electron-phonon coupling in antimonene. While these effects are less obvious in the case of electron-doping, the field effect in hole-doped antimonene results in a considerable variation of the critical temperature, depending on bias voltage. arXiv:1806.08203v4 [cond-mat.supr-con]

Nonlinear optical study of commensurability effects in graphene-hBN heterostructures

“…For example, transition metal dichalcogenides (TMDs) reveal competing charge [1,2] and spin-ordered [3,4], as well as Mott insulating [5,6] states in the mono-and multilayered phases. Also, 2D systems show a superconducting behaviour [7] that was theoretically predicted for black phosphorus [8,9] and antimony [10], and experimentally observed in black phosphorus [11] and various TMDs [12][13][14][15].…”

How to resolve a phonon-associated property into contributions of basic phonon modes

“…The EPC in monolayer Sb has been studied previously [42,43]. Pizzi et al used the deformation potential theory to estimate the electron coupling with the long wavelength LA phonon but neglected the coupling with other phonons [43]; Lugovskoi et al used the perturbation theory and the Wannier interpolation to study the EPC in highly doped 2D Sb and the superconductivity [42], where the BM contributions to the EPC strength are obtained by the energy To answer these questions, here we focus on the scattering of the electrons at the conduction band minimum (CBM), as this state is most populated when Fermi level is within the band gap, and the scattering mechanisms that dominate this state are likely to be also important for other states. The relaxation time (τ) or the scattering rate (1/τ) for the CBM can be calculated as [16]:…”

Interplay between in-plane and flexural phonons in electronic transport of two-dimensional semiconductors

“…The corresponding bands are spin (g s = 2) and valley degenerate (g v = 2). The constant-energy (Fermi) contours at small energies form elliptical pockets [41], meaning that the electron effective mass is different in the direction perpendicular to Γ-M, denoted in Fig. 1 as −P Σ -P Σ .…”