Interlayer Bond Formation in Black Phosphorus at High Pressure

Abstract

Blackphosphorus was compressed at room temperature across the A17, A7 and simple-cubic phases up to 30 GPa, using ad iamond anvil cell and He as pressure transmitting medium. Synchrotron X-ray diffraction showed the persistence of two previously unreported peaks related to the A7 structure in the pressure range of the simple-cubic phase.T he Rietveld refinement of the data demonstrates the occurrence of atwo-step mechanism for the A7 to simple-cubic phase transition, indicating the existence of an intermediate pseudo simple-cubic structure.From ac hemical point of view this study represents ad eep insight on the mechanism of interlayer bond formation during the transformation from the layered A7 to the non-layered simple-cubic phase of phosphorus,o pening new perspectives for the design, synthesis and stabilization of phosphorene-based systems.A ss uperconductivity is concerned, anew experimental evidence to explain the anomalous pressure behavior of T c in phosphorus below 30 GPaisprovided.The current renaissance [1] of black phosphorus (bP), first obtained under high pressure by Bridgman in 1914, [2] is intimately related to the recent synthesis of phosphorene, [3,4] a2 Dc orrugated monoatomic layer of P, where each atom is single-bonded to 3n earest neighbors.T he advent of phosphorene [5][6][7][8][9][10] has indeed dramatically raised the interest of the scientific community about bP,w hose crystalline structure is actually made by the periodic stacking of phosphorene layers, in as imilar way as graphene is related to graphite,a nd the layered phases of this element currently represent an extremely active research topic [11,12] (see the Supporting Information, SI-1).At the moment crystalline bP,which is typically obtained from amorphous red phosphorus at high temperature and/or high pressure, [13,14] is the starting material for the synthesis of phosphorene,either by liquid or mechanical exfoliation. The layered semiconducting orthorhombic bP (A17, Cmce, Z = 8) [15,16] is the thermodynamically stable allotrope of the element at ambient conditions (Figure 1). [17] By increasing pressure at room temperature bP undergoes ac haracteristic phase transition at~5GPa to al ayered semimetallic rhombohedral phase (A7, R3 m, Z = 2), which is reported to transform to ametallic simple-cubic phase (sc, Pm3 m, Z = 1) at~11 GPa. [18][19][20] Thes cs tructure,r arely observed in nature (a-Poa nd high-pressure Ca-III and As-II), [21] is stable up to 103 GPa, where it transforms to an incommensurate modulated structure (P-IV,I M, Cmmm(00g)s00). [22,23] At 137 GPa P-IV converts to asimple-hexagonal phase (P-V,sh, P6/mmm, Z = 1) observed up to 282 GPa, [24,25] which is also ar arely adopted structure.[21] Ab ody-centered cubic structure (bcc), [26,27] successively identified as as uperlattice structure (P-VI, cI16(I4 3d)), has been reported to form above 262 GPa and to be stable up to 340 GPa. [28] However,despite the phase diagram of phosphorus under high pressure being known up to 340 GPa, [28] the details of the tra...

Pressure-Induced Insulator–Metal Transition in Silicon Telluride from First-Principles Calculations

“…41 The M1 and M2 phases of Si 2 Te 3 , on the other hand, are layered. In this regard, Si 2 Te 3 is similar to black phosphorus, 42,43 MoS 2 , 44,45 FePS 3 , 46 FePSe 3 , 47 MoSe 2 , 48 MoTe 2 , 49 MoSSe, 50 Bi 2 Te 3 , 51 and PbFCl, 52 which remain layered at pressures greater than 4−5 GPa.…”

“…To the best of our knowledge, these two structures have not been reported in other 2D chalcogenides.The disappearance of the van der Waals gaps under high pressure has been reported in a number of 2D materials, such as VSe 2 , 36 TiTe 2 , 37 BiTeBr,38 SnSb 2 Te 4 , 39 LaO 0.5 F 0.5 BiS 2 ,40 and InSe.41 The M1 and M2 phases of Si 2 Te 3 , on the other hand, are layered. In this regard, Si 2 Te 3 is similar to black phosphorus,42,43 MoS 2 ,44,45 FePS 3 , 46 FePSe 3 , 47 MoSe 2 ,48 MoTe 2 , 49 MoSSe,50 Bi 2 Te 3 ,51 and PbFCl,52 which remain layered at pressures greater than 4−5 GPa.The dynamical stabilities of M1 and M2 are tested under phonon dispersion calculations using the finite displacement method with supercells of 160 atoms at 10 GPa pressure. The phonon spectra have no imaginary phonon modes, as shown in Figures3a and 4a, confirming their dynamical stabilities.…”

A Perspective on Recent Advances in Phosphorene Functionalization and Its Applications in Devices

“…Above 262 GPa and stable up to 340 GPa a body-centered cubic structure (bcc), later identified as a superlattice structure (P-VI, cI16(I43d)), has been identified. [43] Nevertheless, even if the room T phase diagram of P is known up to 340 GPa, a recent state-of-the-art high pressure synchrotron X-ray diffraction (XRD) experiment has shed new light about the low pressure range, with significant implications concerning the layered structures of P. [45] The XRD patterns, acquired during the room T compression of black phosphorus using a membrane Diamond Anvil Cell (DAC) with He as pressure transmitting medium, revealed indeed two unexpected peaks in the sc structure, appearing at 10.5 GPa and persisting up to 27.6 GPa, the highest investigated pressure. The experimental observation demonstrates that a two-step mechanism rules the transition from the layered A7 to the nonlayered sc structure, as suggested by theoretical predictions.…”

High pressure synthesis of phosphine from the elements and the discovery of the missing (PH3)2H2 tile

“…Rhombohedral A7, another layered structure of phosphorus, was later discovered by compression of P black above 5 GPa 3 . Recently, a high pressure study, based on synchrotron X-ray diffraction (XRD) in Diamond Anvil Cell (DAC), has made another mark in the history of the layered structures of phosphorus, providing a clear insight about the mechanism of interlayer bond formation and significantly raising the pressure limit for the existence of the phosphorus layers up to ~30 GPa at room T 4 , 5 .…”

“… a Phase diagram of phosphorus (black lines), showing the stability regions of the orthorhombic (A17, P black ), rhombohedral (A7) and pseudo simple-cubic (p-sc) structures 4 , 5 . The melting line of H 2 73 (blue line) and laser heating conditions (red point at P = 1.2 GPa, T ≈ 1000 K) are also displayed.…”