Universal Linear Density of States for Tunneling into the Two-Dimensional Electron Gas in a Magnetic field

TL;DR

This study introduces a high-precision measurement technique for the tunneling density of states in a 2D electron gas under magnetic fields, revealing a universal linear energy dependence near the Fermi level and field-dependent slopes.

Contribution

It presents a novel measurement method that accurately captures the TDOS without distortions, uncovering a universal linear density of states in a 2D electron gas in magnetic fields.

Findings

TDOS shows a linear energy dependence near the Fermi level.

The slope of the linear gap varies strongly with magnetic field.

A new model for the low-energy gap is suggested.

Abstract

A new technique permits high fidelity measurement of the tunneling density of states (TDOS) of the two-dimensional electron gas. The obtained TDOS contains no distortions arising from low 2D in-plane conductivity and includes the contribution from localized tunneling sites. In a perpendicular magnetic field, a pseudogap develops in the TDOS at the Fermi level. Improved sensitivity enables resolution of a linear dependence of the TDOS on energy near the Fermi energy. The slopes of this linear gap are strongly field dependent. The data are suggestive of a new model of the gap at low energies.