Giant Phononic Anisotropy and Unusual Anharmonicity of Phosphorene: Interlayer Coupling and Strain Engineering

• DOI: 10.1002/adfm.201404294
• Publication Date: 2015-02-16T15:43:13Z
• Authors: Yongqing Cai; Qingqing Ke; Gang Zhang; Yuan Ping Feng; Vivek B. Shenoy; Yong‐Wei Zhang
• Keywords: Phosphorene; Zigzag; Brillouin zone; Strain engineering; Nanoelectronics

Phosphorene, an emerging elemental 2D direct band gap semiconductor with fascinating structural and electronic properties distinctively different from other materials such as graphene MoS 2 , is promising for novel nanoelectronic optoelectronic applications. Phonons, one of the most important collective excitations, are at heart device performance, their interactions electrons photons govern carrier mobility light‐emitting efficiency material. Here, through a detailed first‐principles study, it demonstrated that monolayer phosphorene exhibits giant phononic anisotropy, remarkably, this anisotropy squarely opposite to its counterpart can be tuned effectively by strain engineering. By sampling whole Brillouin zone phosphorene, several “hidden” directions found, along which small‐momentum phonons “frozen” possess smallest degree anharmonicity. Unexpectedly, these intrinsically usually‐studied armchair zigzag directions. Light also shed on interlayer coupling few‐layer examining rigid‐layer vibrations. These highly anisotropic strain‐tunable characteristics offer new possibilities applications in thermal management, thermoelectronics, nanoelectronics, phononics.