title: Anomalous piezoelectricity in two-dimensional graphene nitride nanosheets.
abstract: Piezoelectricity is a unique property of materials that permits the conversion of mechanical stimuli into electrical and vice versa. On the basis of crystal symmetry considerations, pristine carbon nitride (C3N4) in its various forms is non-piezoelectric. Here we find clear evidence via piezoresponse force microscopy and quantum mechanical calculations that both atomically thin and layered graphitic carbon nitride, or graphene nitride, nanosheets exhibit anomalous piezoelectricity. Insights from ab inito calculations indicate that the emergence of piezoelectricity in this material is due to the fact that a stable phase of graphene nitride nanosheet is riddled with regularly spaced triangular holes. These non-centrosymmetric pores, and the universal presence of flexoelectricity in all dielectrics, lead to the manifestation of the apparent and experimentally verified piezoelectric response. Quantitatively, an e11 piezoelectric coefficient of 0.758 C m(-2) is predicted for C3N4 superlattice, significantly larger than that of the commonly compared α-quartz.
authors: Department of Mechanical Engineering, University of Houston, Houston, Texas 77204, USA.
authors: Matthew
authors: M
authors: Zelisko
authors: Department of Materials Engineering, Kasetsart University, Bangkok 10900, Thailand.
authors: Yuranan
authors: Y
authors: Hanlumyuang
authors: Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
authors: Shubin
authors: S
authors: Yang
authors: Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195, USA.
authors: Yuanming
authors: Y
authors: Liu
authors: Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195, USA.
authors: Chihou
authors: C
authors: Lei
authors: Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195, USA.
authors: Jiangyu
authors: J
authors: Li
authors: Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
authors: Pulickel M
authors: PM
authors: Ajayan
authors: 1] Department of Mechanical Engineering, University of Houston, Houston, Texas 77204, USA [2] Department of Physics, University of Houston, Houston, Texas 77204, USA.
authors: Pradeep
authors: P
authors: Sharma