Renormalized Landau quasiparticle dispersion revealed by photoluminescence spectra from a two-dimensional Fermi liquid at the MgZnO/ZnO heterointerface

摘要

We analyze the low-temperature photoluminescence spectra from two-dimensional electron systems (2DESs) confined at Mg_xZn_(1-x)O/ZnO heterojunctions as the electron density is decreased from 2.3 × 10~(12) to 3.5 × 10~(11) cm~(-2). The value of the quasiparticle optical density-of-states mass is directly extracted from the width of the 2DES photoluminescence band and is shown to renormalize and double from the value close to that of bulk ZnO material, 0.3m_0 (m_0 is the bare electron mass), to 0.6m_0 due to electron-electron interactions as the interaction parameter r_s increases from 2.4 to 6.5. The experimentally probed quasiparticle energies far exceed the limits of Landau's Fermi-liquid theory.