Ferroelectricity and Phase Transitions in Monolayer Group-IV Monochalcogenides

Fei, Ruixiang; Kang, Wei; Yang, Li

doi:10.1103/physrevlett.117.097601

Cited by 575 publications

(621 citation statements)

References 58 publications

Supporting

Mentioning

573

Contrasting

Unclassified

Order By: Relevance

“…The spontaneous in-plane polarization (P s ) estimated in monolayer GeSe can reach to 3.5×10 -10 C/m, which is well consistent with previous works [39][40][41]. [12], the spontaneous valley polarization is induced by ferromagnetism.…”

Section: Resultssupporting

confidence: 76%

See 1 more Smart Citation

Electrically tunable polarizer based on 2D orthorhombic ferrovalley materials

et al. 2017

View full text Add to dashboard Cite

The concept of ferrovalley materials has been proposed very recently. The existence of spontaneous valley polarization, resulting from ferromagnetism, in such hexagonal two-dimensional materials makes nonvolatile valleytronic applications realizable. Here, we introduce a new member of ferrovalley family with orthorhombic lattice, i.e. monolayer group-IV monochalcogenides (GIVMs), in which the intrinsic valley polarization originates from ferroelectricity, instead of ferromagnetism. Combining the group theory analysis and first-principles calculations, we demonstrate that, different from the valley-selective circular dichroism in hexagonal lattice, linearly polarized optical selectivity for valleys exists in the new type of ferrovalley materials. On account of the distinctive property, a prototype of electrically tunable polarizer is realized. In the ferrovalley-based polarizer, a laser beam can be optionally polarized in x-or y-direction, depending on the ferrovalley state controlled by external electric fields. Such a device can be further optimized to emit circularly polarized radiation with specific chirality and to realize the tunability for operating wavelength. Therefore, we show that two-dimensional orthorhombic ferrovalley materials are the promising candidates to provide an advantageous platform to realize the polarizer driven by electric means, which is of great importance in extending the practical applications of valleytronics.

show abstract

Section: Resultssupporting

confidence: 76%

“…In analogy to black phosphorus [33], group-IV monochalcogenides [34][35][36][37][38][39][40][41] exhibit waved structures. For paravalley materials with hexagonal lattice, the circularly polarized optical selectivity for valleys has been proposed which is essentially rooted in conservation of overall azimuthal quantum number [42].…”

Section: Resultsmentioning

confidence: 99%

Electrically tunable polarizer based on 2D orthorhombic ferrovalley materials

et al. 2017

View full text Add to dashboard Cite

show abstract

“…To calculate the electric polarization of monolayer PbS, we estimate the thickness as twice the distance between S and Pb atom which is roughly half of the lattice constant of bulk PbS. Similar approximations have also done in other several works [24][25][26].The calculated spontaneous polarizations of path I (optimized buckled lattice parameters) and path II (optimized planar lattice parameters) are 0.2 C/m 2 and 0.1 C/m 2 , respectively.…”

Section: Bistabilitymentioning

confidence: 79%

“…To compare the electric polarization of monolayer PbS to the typical bulk ferroelectrics, we approximate the thickness as twice the distance between S and Pb atom which is roughly half of the lattice constant of bulk PbS. Similar approximations have also been used in other several works [24][25][26].…”

mentioning

confidence: 99%

Two-dimensional square buckled Rashba lead chalcogenides

et al. 2017

View full text Add to dashboard Cite

We propose the lead sulphide (PbS) monolayer as a 2D semiconductor with a large Rashba-like spin-orbit effect controlled by the out-of-plane buckling. The buckled PbS conduction band is found to possess Rashba-like dispersion and spin texture at the M and Γ points, with large effective Rashba parameters of λ ∼ 5 eVÅ and λ ∼ 1 eVÅ, respectively. Using a tight-binding formalism, we show that the Rashba effect originates from the very large spin-orbit interaction and the hopping term that mixes the in-plane and out-of-plane p orbitals of Pb and S atoms. The latter, which depends on the buckling angle, can be controlled by applying strain to vary the spin texture as well as the Rashba parameter at Γ and M . Our density functional theory results together with tight-binding formalism provide a unifying framework for designing Rashba monolayers and for manipulating their spin properties.Introduction-Over the past two decades there has been a growing interest in materials with strong spin-orbit interaction (SOI), as they are of a profound importance for fundamental understanding of quantum phenomena at the atomic level and applications to spintronics. This relativistic interaction is linked to important effects such as Rashba, Zeeman, spin-Hall effect, and topological insulator (TI) states [1][2][3][4].

show abstract

“…The field of 2D materials has expanded greatly in the past few years, featuring a broad range of applications for electronic, photonic and piezoelectric devices [1][2][3][4], as well as exciting new physics to be realized, such as 2D ferroelectricity, ferromagnetism and exciton condensate [5][6][7][8]. Almost all the applications are premised on a good understanding the electronic properties of the material, especially the quasiparticle band gap.…”

Section: Introductionmentioning

confidence: 99%

Renormalization of the quasiparticle band gap in doped two-dimensional materials from many-body calculations

Gao

Yang

2017

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

Doped free carriers can substantially renormalize electronic self-energy and quasiparticle band gaps of two-dimensional (2D) materials. However, it is still challenging to quantitatively calculate this many-electron effect, particularly at the low doping density that is most relevant to realistic experiments and devices. Here we develop a first-principles-based effective-mass model within the GW approximation and show a dramatic band gap renormalization of a few hundred meV for typical 2D semiconductors. Moreover, we reveal the roles of different many-electron interactions: The Coulomb-hole contribution is dominant for low doping densities while the screened-exchange contribution is dominant for high doping densities. Three prototypical 2D materials are studied by this method, h-BN, MoS2, and black phosphorus, covering insulators to semiconductors. Especially, anisotropic black phosphorus exhibits a surprisingly large band gap renormalization because of its smaller density-of-state that enhances the screened-exchange interactions. Our work demonstrates an efficient way to accurately calculate band gap renormalization and provides quantitative understanding of doping-dependent many-electron physics of general 2D semiconductors.

show abstract

Ferroelectricity and Phase Transitions in Monolayer Group-IV Monochalcogenides

Cited by 575 publications

References 58 publications

Electrically tunable polarizer based on 2D orthorhombic ferrovalley materials

Electrically tunable polarizer based on 2D orthorhombic ferrovalley materials

Two-dimensional square buckled Rashba lead chalcogenides

Renormalization of the quasiparticle band gap in doped two-dimensional materials from many-body calculations

Contact Info

Product

Resources

About