Phonon sidebands of color centers in hexagonal boron nitride
Phonon sidebands of color centers in hexagonal boron nitride
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DOI：
10.1103/physrevb.100.125305
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发表时间：
2019-09-16
影响因子：
3.7
通讯作者：
Ramsay, A. J.
中科院分区：
文献类型：
--
作者：
Khatri, P.;Luxmoore, I. J.;Ramsay, A. J.
将六方氮化硼色心声子边带的低温光致发光谱与独立玻色子模型进行了比较。我们推断，LA-声子边带所描述的变形耦合成比例的面内应变，从而在声子浴，有效地二维。对于光学声子，观察到尖锐的共振接近声子色散的转折点。我们推断，TO-电子耦合所描述的变形耦合成比例的面内晶格位移，导致在一个TO浴，也是有效的二维。相比之下，对于LO分支，我们推断Frohlich耦合取决于相邻层之间的相互作用，并提出200 meV的峰值是一个签名的几层样品。这项工作突出了电子-声子耦合的h-BN的层状结构所产生的功能。
Low temperature photoluminescence spectra of the phonon sidebands of a color center in hexagonal boron nitride are compared to an independent boson model. We infer that the LA-phonon sideband is described by deformation coupling proportional to in-plane strain, resulting in a phonon bath that is effectively two-dimensional. For optical phonons, sharp resonances close to turning points in the phonon dispersion are observed. We infer that the TO-electron coupling is described by deformation coupling proportional to in-plane lattice displacement, resulting in a TO bath that is also effectively two-dimensional. By contrast, for the LO branches we infer that the Frohlich coupling depends on the interactions between adjacent layers, and propose that the 200-meV peak is a signature of a few-layer sample. This work highlights features of electron-phonon coupling that arise from the layered structure of h-BN.