Finite-temperature Fermi-edge singularity in tunneling studied using random telegraph signals

TL;DR

This paper demonstrates how random telegraph signals in silicon transistors at millikelvin temperatures can be used to study tunneling phenomena, revealing a finite-temperature Fermi-edge singularity and linking defect levels to two-state dissipation.

Contribution

It introduces a novel experimental approach using telegraph signals to investigate tunneling and Fermi-edge singularity at finite temperatures in silicon transistors.

Findings

Tunneling rate peaks when defect levels align with Fermi energy

Experimental results agree with finite-temperature Fermi-edge singularity theory

Defect levels are identified as sources of two-state dissipation phenomena

Abstract

We show that random telegraph signals in metal-oxide-silicon transistors at millikelvin temperatures provide a powerful means of investigating tunneling between a two-dimensional electron gas and a single defect state. The tunneling rate shows a peak when the defect level lines up with the Fermi energy, in excellent agreement with theory of the Fermi-edge singularity at finite temperature. This theory also indicates that defect levels are the origin of the dissipative two-state systems observed previously in similar devices.