González J, Perfetto E
Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain.
Phys Rev Lett. 2008 Oct 24;101(17):176802. doi: 10.1103/PhysRevLett.101.176802. Epub 2008 Oct 21.
We address the question of how large can the lifetime of electronic states be at low energies in graphene, below the scale of the optical phonon modes. For this purpose, we study the many-body effects at the K point of the spectrum, which induce a strong coupling between electron-hole pairs and out-of-plane phonons. We show the existence of a soft branch of hybrid states below the electron-hole continuum when graphene is close to the charge neutrality point, leading to an inverse lifetime proportional to the cube of the quasiparticle energy. This implies that a crossover should be observed in transport properties, from such a slow decay rate to the lower bound given at very low energies by the decay into acoustic phonons.
我们探讨了在低于光学声子模式尺度的石墨烯中，低能电子态的寿命能有多长这一问题。为此，我们研究了能谱K点处的多体效应，这种效应会在电子 - 空穴对与面外声子之间引发强耦合。我们发现，当石墨烯接近电荷中性点时，在电子 - 空穴连续区之下存在一个混合态的软支，这导致逆寿命与准粒子能量的立方成正比。这意味着在输运性质中应能观察到一个转变，即从如此缓慢的衰减率转变为在极低能量下由衰变成声学声子所给出的下限。
