Giant Anisotropic Raman Response of Encapsulated Ultrathin Black Phosphorus by Uniaxial Strain

Yanyong Li, Zhixin Hu, Shenghuang Lin, Sin Ki Lai, Wei Ji, Shu Ping Lau

Research output: Journal article publicationJournal articleAcademic researchpeer-review

60 Citations (Scopus)

Abstract

KGaA, Weinheim The giant anisotropic Raman response of encapsulated ultrathin black phosphorus (BP) is reported by uniaxial strain. A modified bending technique is employed to apply precise uniaxial tensile strain along the zigzag or armchair direction of the ultrathin BP encapsulated by a layer of polymethyl methacrylate. The Raman shift rates of the A1g, B2g, and A2gmodes are significantly distinct for strain applied along different directions. For the strain applied along zigzag direction, the Raman shift rate of the B2gmode can reach a remarkable value of ≈−11 cm−1/% strain. In addition, the Grüneisen parameter is as high as ≈2.5, which is the largest among all the reported common 2D materials. Density functional perturbation theory calculations are performed to understand the exceptional anisotropic strain response discovering that not only the bond lengths but also the bond angels are changed in the strained ultrathin BP, which lead to the giant anisotropic Raman response. Furthermore, an alternative method based entirely on the strained ultrathin BP and nonpolarized Raman spectroscopy is demonstrated to determine the crystallographic orientations of ultrathin BP. This work paves a way to study the strain-induced anisotropic electrical conductance and magnetotransport properties of BP.
Original languageEnglish
Article number1600986
JournalAdvanced Functional Materials
Volume27
Issue number19
DOIs
Publication statusPublished - 18 May 2017

Keywords

  • anisotropy
  • black phosphorus
  • Grüneisen parameter
  • Raman spectroscopy
  • uniaxial strain

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Condensed Matter Physics
  • Electrochemistry

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