Determining the local density of states in the constant current STM mode

Abstract

We present an alternative scheme to determine the local density of states (LDOS) of a sample using data obtained via scanning tunneling spectroscopy (STS). Using either the tunneling current as a function of applied bias voltage or the tip-sample separation as a function of applied bias voltage, the LDOS can be determined via a numerical fitting algorithm. This fitting algorithm makes use of the one-dimensional Simmons tunnel barrier model without introducing any further mathematical approximations. By ways of a simulated LDOS, the proposed method is compared to existing LDOS extraction methods for both positive and negative biases, and the differences between the methods are discussed. © 2013 American Physical Society.