Charge density wave and superconducting phase in monolayer InSe

Alidoosti, Mohammad; Esfahani, Davoud Nasr; Asgari, Reza

doi:10.1103/physrevb.103.035411

Cited by 18 publications

(17 citation statements)

References 50 publications

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“…In addition, we do not find any additional Bragg peak in the charge susceptibility at twice the Fermi wave vector 2k F , which would indicate a charge instability due to the electron-phonon mechanism. This fact suggests that many-body effects in the monolayer InSe are driven by strong Coulomb correlations rather than by the electron-phonon mechanism as suggested previously [18].…”

supporting

confidence: 69%

“…In particular, it has been shown that hole states in this material undergo significant renormalization due to the interaction with acoustic phonons, which gives rise to the appearance of unusual temperature-dependent optical excitations [17]. Also, a strong electron-phonon interaction may result in a charge density wave (CDW) instability predicted recently [18]. At the same time, monolayer InSe is expected to possess strong electronic Coulomb correlations that have not been accurately studied yet.…”

mentioning

confidence: 97%

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Coexisting charge density wave and ferromagnetic instabilities in monolayer InSe

Stepanov¹,

Harkov²,

Rösner³

et al. 2021

Preprint

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Recently fabricated InSe monolayers exhibit remarkable characteristics that indicate the potential of this material to host a number of many-body phenomena. Here, we consistently describe collective electronic effects in hole-doped InSe monolayers using advanced many-body techniques. To this end, we derive a realistic electronicstructure model from first principles that takes into account the most important characteristics of this material, including a flat band with prominent van Hove singularities in the electronic spectrum, strong electron-phonon coupling, and weakly-screened long-ranged Coulomb interactions. We calculate the temperature-dependent phase diagram as a function of band filling and observe that this system is in a regime with coexisting charge density wave and ferromagnetic instabilities that are driven by strong electronic Coulomb correlations. This regime can be achieved at realistic doping levels and high enough temperatures, and can be verified experimentally. We find that the electron-phonon interaction does not play a crucial role in these effects, effectively suppressing the local Coulomb interaction without changing the qualitative physical picture.

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supporting

confidence: 69%

mentioning

confidence: 97%

Coexisting charge density wave and ferromagnetic instabilities in monolayer InSe

Stepanov¹,

Harkov²,

Rösner³

et al. 2021

Preprint

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“…To represent the EPC strength, we calculate λ q,ν , as a dimensionless value associated with a single phonon momentum q and mode ν and it can be written as [39,40]:…”

Section: Numerical Examples: Dfpt Simulationsmentioning

confidence: 99%

“…Though the number of q's that are active in the scattering process is large, we obtain a total λ of about 0.6 in the electron-doped case, while the large number of active q's accompanied with a remarkable amount of the EPC strength give rise to a total λ ∼ 8 in the hole-doped case. The reason for the difference is the fact that the DOS for the hole-doped case is appreciably larger than that in the electron-doped case [40]. Moreover, the discrepancy between the EPC values can be understood based on the density of states, the g mn,ν (q, ω), and various lattice dielectric screenings of TMDCs [52,53].…”

Section: Numerical Examples: Dfpt Simulationsmentioning

confidence: 99%

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

Alidoosti,

Esfahani,

Asgari

2022

Preprint

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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.

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“…This character leads to an intense softening at specific qs in some branches of the phonon spectrum, known as the Kohn anomaly [28,29], and in some cases, a charge density wave (CDW) instability will appear in the form of the imaginary modes for some particular phonon wave vectors (q CDW ) when the temperature is below T CDW . Accordingly, access to such a high T c can be prohibited by this instability [22,30]. Therefore, a more uniform distribution of λ in terms of phonon wave vectors over the 1BZ is more favorable to gain large T c , while, the formation of the CDW phase becomes less likely.…”

Section: Introductionmentioning

confidence: 99%

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

Alidoosti,

Esfahani,

Asgari

2022

Preprint

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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.

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Charge density wave and superconducting phase in monolayer InSe

Cited by 18 publications

References 50 publications

Coexisting charge density wave and ferromagnetic instabilities in monolayer InSe

Coexisting charge density wave and ferromagnetic instabilities in monolayer InSe

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

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

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