Raman study of black phosphorus up to 13 GPa

Akahama, Yuichi; Kobayashi, Masakazu; Kawamura, Haruki

doi:10.1016/s0038-1098(97)00325-6

Cited by 76 publications

(87 citation statements)

References 18 publications

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“…Here, the D direction is along the 45°direction to both the x and y directions within the x-y plane. We observe three Raman peaks in thin film BP at around 470, 440 and 365 cm À 1 , corresponding to the A 2 g , B 2g and A 1 g modes, regardless of the polarization, which agrees well with previous observations in bulk BP crystals 44 . These sharp modes correspond to the unique orthorhombic crystalline phosphorus structure, confirming that the material studied in this work is indeed orthorhombic BP.…”

Section: Resultssupporting

confidence: 92%

Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics

2014

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Graphene and transition metal dichalcogenides (TMDCs) are the two major types of layered materials under intensive investigation. However, the zero-bandgap nature of graphene and the relatively low mobility in TMDCs limit their applications. Here we reintroduce black phosphorus (BP), the most stable allotrope of phosphorus with strong intrinsic in-plane anisotropy, to the layered-material family. For 15-nm-thick BP, we measure a Hall mobility of 1,000 and 600 cm 2 V À 1 s À 1 for holes along the light (x) and heavy (y) effective mass directions at 120 K. BP thin films also exhibit large and anisotropic in-plane optical conductivity from 2 to 5 mm. Field-effect transistors using 5 nm BP along x direction exhibit an on-off current ratio exceeding 10 5 , a field-effect mobility of 205 cm 2 V À 1 s À 1 , and good current saturation characteristics all at room temperature. BP shows great potential for thin-film electronics, infrared optoelectronics and novel devices in which anisotropic properties are desirable.

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Section: Resultssupporting

confidence: 92%

Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics

2014

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“…We find that the critical pressure of thermodynamic stability P T for bulk BP with orthorhombic phase is 4.6 GPa (see Figure S2), very close to the experimental result (4.7 GPa), 29 which indicates a structural phase transition from a A17 (orthorhombic) phase to a A7 (rhombohedral) phase.…”

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confidence: 86%

Robust and Pristine Topological Dirac Semimetal Phase in Pressured Two-Dimensional Black Phosphorus

et al. 2017

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Very recently, in spite of various efforts in searching for two dimensional topological Dirac semimetals (2D TDSMs) in phosphorene, there remains a lack of experimentally efficient way to activate such phase transition and the underlying mechanism for the topological phase acquisition is still controversial. Here, from first-principles calculations in combination with a band-sorting technique based on k·p theory, a layer-pressure 1 topological phase diagram is obtained and some of the controversies are clarified. We demonstrate that, compared with tuning by external electric-fields, strain or doping by adsorption, hydrostatic pressure can be an experimentally more feasible way to activate the topological phase transition for 2D TDSM acquisition in phosphorene. More importantly, the resultant TDSM state is a pristine phase possessing a single pair of symmetry-protected Dirac cones right at the Fermi level, in startling contrast to the pressured bulk black phosphorous where only a carrier-mixed Dirac state can be obtained. We corroborate that the Dirac points are robust under external perturbation as long as the glide-plane symmetry preserves. Our findings provide a means to realize 2D pristine TDSM in a more achievable manner, which could be crucial in the realization of controllable TDSM states in phosphorene and related 2D materials.Two dimensional (2D) Dirac semimetals, in which Dirac points cross the Fermi level (E F ) being protected by nonsymmorphic crystal symmetries, was first proposed by Young and Kane in 2015.1 Very recent progress on the strain or electric-field modified phosphorene, as a representative of the rare candidates, has established a link between Dirac cones and the topological nature. 2-4Given the experimental discovery of three dimensional (3D) topological Dirac semimetals (Na 3 Bi, 5Cd 3 As 2 6) and α-Sn on InSb(111) substrate, 7it is natural to ask whether the 2D topological Dirac semimetals (TDSMs) can also be realized in an experimentally feasible manner.A simple mechanism for a 2D TDSM phase acquisition has been proposed based on the Stark effect in phosphorene thin films by applying an external electric field. 3,8However, applying an exceptionally giant electric field on such a system is difficult to realize experimentally (the value of the field required is ∼0.5 V/Å for a four-layer phosphorene 8 ). On the basis of the same mechanism, the experimentally observed Dirac semimetal state, from potassium doping of few-layer phosphorene, is actually an electron-doped TDSM. However, a pristine TDSM in 2D is highly desirable as it can be tuned to be topological insulators (TIs) or Weyl semimetals by explicit breaking of symmetries. In this regard, in-plane strain has been proposed as a possible means to induce Dirac cones in monolayer or bilayer phos-2 phorene, [10][11][12] whereas the critical strain (as large as ∼10% uniaxial strain or 5% biaxial strain based on the DFT-PBE level 11) is difficult to be experimentally realized, particularly for the biaxial strain in strong-anisotro...

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“…Further, the direct band gap (∼ 0.3eV ) of BP arises from the out-of-plane p z -like orbitals of phosphorus and hence can be strongly modulated by pressure or c-axis strain. Not surprisingly, the effect of pressure was studied on crystal structure and electronic properties in the early work [16][17][18][19][20][21][22] . It has anisotropic compressibility: lattice parameters a and c decrease more in comparison with the lattice parameter b with increasing pressure.…”

Section: Introductionmentioning

confidence: 99%

Raman anomalies as signatures of pressure induced electronic topological and structural transitions in black phosphorus: Experiments and theory

et al. 2017

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We report high pressure Raman experiments of Black phosphorus (BP) up to 24 GPa. The line widths of first order Raman modes A 1 g , B2g and A 2 g of the orthorhombic phase show a minimum at 1.1 GPa. Our first-principles density functional analysis reveals that this is associated with the anomalies in electron-phonon coupling at the semiconductor to topological insulator transition through inversion of valence and conduction bands marking a change from trivial to nontrivial electronic topology. The frequencies of B2g and A 2 g modes become anomalous in the rhombohedral phase at 7.4 GPa, and new modes appearing in the rhombohedral phase show anomalous softening with pressure. This is shown to originate from unusual structural evolution of black phosphorous with pressure, based on first-principles theoretical analysis.

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Raman study of black phosphorus up to 13 GPa

Cited by 76 publications

References 18 publications

Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics

Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics

Robust and Pristine Topological Dirac Semimetal Phase in Pressured Two-Dimensional Black Phosphorus

Raman anomalies as signatures of pressure induced electronic topological and structural transitions in black phosphorus: Experiments and theory

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