Full Momentum and Energy Resolved Spectral Function of a 2D Electronic System: Part I

The single-particle spectral function measures the density of electronic states (DOS) in a material as a function of both momentum and energy, providing central insights into phenomena such as superconductivity and Mott insulators. While scanning tunneling microscopy (STM) and other tunneling methods have provided partial spectral information [1] , until now only angle-resolved photoemission spectroscopy (ARPES) has permitted a comprehensive determination of the spectral function of materials in both momentum and energy. However, ARPES operates only on electronic systems at the material surface and cannot work in the presence of applied magnetic fields. Here, we demonstrate a new method (MERTS) for determining the full momentum and energy resolved electronic spectral function of a two-dimensional (2D) electronic system embedded in a semiconductor [2]. The technique remains operational in the presence of large externally applied magnetic fields and functions even for electronic systems with zero electrical conductivity or with zero electron density. *[1] O. E. Dial et al. Nature 448, 176, (2007) [2] J. Jang, H. M. Yoo, L. N. Pfeiffer, K. West, K. W. Baldwin, and R. C. Ashoori, Science (Accepted, 2017)