Effect of pressure on bonding in black phosphorus

Cartz, L.; Srinivasa, S. R.; Riedner, R. J.; Jorgensen, J. D.; Worlton, T.G.

doi:10.1063/1.438523

Cited by 258 publications

(212 citation statements)

References 13 publications

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“…Application of further pressure generates two reversible structural transitions: the first one, from an orthorhombic to a rhombohedral phase occurring at 5.5 GPa 13 , while the second is from a rhombohedral to a simple cubic phase at about 11 GPa. 14 It is striking to note that the compressibility along the zigzag chains, both from experiment 15 and density-functional calculations, is small as compared to the other two directions, including the c direction, along which the phosphorous planes are thought to be held together by the weak, van der Waals forces.…”

Section: Introductionmentioning

confidence: 99%

Electronic structure and anisotropic Rashba spin-orbit coupling in monolayer black phosphorus

2015

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We investigate the electronic structure of the monolayer black phosphorus (BP) using density functional methods both with and without an applied electric field. We find that a simple one-band tight-binding Hamiltonian based on the pz orbitals and nearest-neighbor hopping is sufficient to describe the band structure in the gap region rather well and justification for this is given from symmetry arguments. The anisotropic nature of the band structure leads in turn to an anisotropic Rashba effect, where the magnitude of the spin splitting caused by an applied electric field is not only momentum dependent, but also depends on the direction of k. The Rashba Hamiltonian is generalized for the anisotropic case, which reads: HR = αR( σ × k ′ ) ·ẑ, where the scaled momentum k ′ contains the anisotropy effect. The Rashba effect is studied quantitatively for BP from ab initio density-functional calculations in the presence of an applied electric field. A by-product of this work is the demonstration that the strength of the spin-orbit coupling for the outermost electrons in the atoms, which are relevant for the solids, increases only as the Landau-Lifshitz Z 2 scaling with the atomic number Z, rather than the higher power Z 4 scaling, as sometimes thought.

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Section: Introductionmentioning

confidence: 99%

Electronic structure and anisotropic Rashba spin-orbit coupling in monolayer black phosphorus

2015

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“…This essentially results in structural change for black phosphorus under high pressure. [29,30] As a matter of fact, black phosphorus undergoes two reversible structural transitions at high pressures. The first transition, from orthorhombic to rhombohedral phase occurs around 5.5 GPa at room temperature, accompanied by displacement of the puckered layers and a volume change.…”

Section: Crystal Structurementioning

confidence: 99%

Semiconducting black phosphorus: synthesis, transport properties and electronic applications

et al. 2015

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“…Inside a single layer, each phosphorus atom is covalently bonded with three adjacent phosphorus atoms to form a puckered honeycomb structure [2][3][4] (Fig. 1a).…”

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confidence: 99%

Black phosphorus field-effect transistors

et al. 2014

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Black phosphorus is a layered material in which individual atomic layers are stacked together by Van der Waals interactions, much like bulk graphite 1 . Inside a single layer, each phosphorus atom is covalently bonded with three adjacent phosphorus atoms to form a puckered honeycomb structure [2][3][4] (Fig. 1a). The three bonds take up all three valence electrons of phosphorus, so unlike graphene 5,6 a monolayer black phosphorus (termed "phosphorene") is a semiconductor with a predicted direct band gap of ~ 2 eV at the Γ point of the first Brillouin zone 7 . For few-layer phosphorene, interlayer interactions reduce the band gap for each layer 3 added, and eventually reach ~ 0.3 eV (refs 8-11) for bulk black phosphorus. The direct gap also moves to the Z point as a consequence 7,12 . Such a band structure provides a much needed gap for the field-effect transistor (FET) application of two dimensional (2D) materials such as graphene, and the thickness-dependent direct band gap may lead to potential applications in optoelectronics, especially in the infrared regime. In addition, observations of phase transition from semiconductor to metal 13,14 and superconductor under high pressure 15,16 We next fabricate few-layer phosphorene FETs with a back-gate electrode (see Fig. 2a). A scotch tape based mechanical exfoliation method is employed to peel thin flakes from bulk crystal onto degenerately doped silicon wafer covered with a layer of thermally grown silicon dioxide. Optical microscopy and atomic force microscopy (AFM) are used to hunt thin flake samples and determine their thickness (Fig. 2a). The switching behaviour of our few-layer phosphorene transistor at room temperature is characterized in vacuum (~ 10 -6 mBar), in a configuration depicted in -30 V to 0 V, the channel switches from "on" state to "off" state, and a drop in drain current by a factor of ~ 10 5 is observed. The measured drain current modulation is 4 orders of magnitude larger than that in graphene (due to its lack of bandgap), and 5 approaches the value recently reported in MoS2 devices 17 . Such a high drain current modulation makes black phosphorus thin film a promising material for applications in digital electronics 22 . Similar switching behaviour (with varying drain current modulation) is observed on all black phosphorous thin film transistors with thicknesses up to 50 nm. We note that the "on" state current of our devices has not yet reached saturation, due to the fact that the doping level is limited by the break-down electric field of the SiO2 back-gate dielectric. It is therefore possible to achieve even higher drain current modulation by using high-k materials as gate dielectrics for higher doping. Meanwhile, a subthreshold swing (SS) of ~ 5 V/decade is observed, which is much larger than the SS in commercial Si-based devices (~ 70 mV/decade).We note that the SS in our devices varies from sample to sample (from ~ 3.7 V/decade to ~ 13.3 V/decade), and is on the same order of magnitude as reported in multilayerMoS2 devices with a simila...

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Effect of pressure on bonding in black phosphorus

Cited by 258 publications

References 13 publications

Electronic structure and anisotropic Rashba spin-orbit coupling in monolayer black phosphorus

Electronic structure and anisotropic Rashba spin-orbit coupling in monolayer black phosphorus

Semiconducting black phosphorus: synthesis, transport properties and electronic applications

Black phosphorus field-effect transistors

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