Strain-engineered direct-indirect band gap transition and its mechanism in two-dimensional phosphorene

Xihong Peng, Qun Wei, Andrew Copple

Research output: Contribution to journalArticle

442 Citations (Scopus)

Abstract

Recently fabricated two-dimensional phosphorene crystal structures have demonstrated great potential in applications of electronics. In this paper, strain effect on the electronic band structure of phosphorene was studied using first-principles methods including density functional theory (DFT) and hybrid functionals. It was found that phosphorene can withstand a tensile stress and strain up to 10 N/m and 30%, respectively. The band gap of phosphorene experiences a direct-indirect-direct transition when axial strain is applied. A moderate -2% compression in the zigzag direction can trigger this gap transition. With sufficient expansion (+11.3%) or compression (-10.2% strains), the gap can be tuned from indirect to direct again. Five strain zones with distinct electronic band structure were identified, and the critical strains for the zone boundaries were determined. Although the DFT method is known to underestimate band gap of semiconductors, it was proven to correctly predict the strain effect on the electronic properties with validation from a hybrid functional method in this work. The origin of the gap transition was revealed, and a general mechanism was developed to explain energy shifts with strain according to the bond nature of near-band-edge electronic orbitals. Effective masses of carriers in the armchair direction are an order of magnitude smaller than that of the zigzag axis, indicating that the armchair direction is favored for carrier transport. In addition, the effective masses can be dramatically tuned by strain, in which its sharp jump/drop occurs at the zone boundaries of the direct-indirect gap transition.

Original languageEnglish (US)
Article number085402
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume90
Issue number8
DOIs
StatePublished - Aug 4 2014

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Electron transitions
Energy gap
electronics
Band structure
Density functional theory
density functional theory
axial strain
tensile stress
Carrier transport
Tensile strain
functionals
Tensile stress
Electronic properties
actuators
Electronic equipment
Crystal structure
orbitals
crystal structure
expansion
Semiconductor materials

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Strain-engineered direct-indirect band gap transition and its mechanism in two-dimensional phosphorene. / Peng, Xihong; Wei, Qun; Copple, Andrew.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 90, No. 8, 085402, 04.08.2014.

Research output: Contribution to journalArticle

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