Detection and measurement of spin-dependent dynamics in random telegraph signals

TL;DR

This paper presents a statistical method to analyze spin-dependent electron tunneling dynamics in quantum dots using random telegraph signals, enabling measurements in the thermal energy regime and confirming magnetic field effects.

Contribution

Developed a novel statistical approach to extract spin-dependent tunneling information from RTS, allowing studies in thermal energy conditions and independent measurement of spin state rates.

Findings

Spin-dependent tunneling rates are measurable from RTS.

External magnetic field decreases tunneling rates for the spin excited state.

Method enables analysis of spin dynamics in thermal regimes.

Abstract

A quantum point contact was used to observe single-electron fluctuations of a quantum dot in a GaAs heterostructure. The resulting random telegraph signals (RTS) contain statistical information about the electron spin state if the tunneling dynamics are spin-dependent. We develop a statistical method to extract information about spin-dependent dynamics from RTS and use it to demonstrate that these dynamics can be studied in the thermal energy regime. The tunneling rates of each spin state are independently measured in a finite external magnetic field. We confirm previous findings of a decrease in overall tunneling rates for the spin excited state compared to the ground state as an external magnetic field is increased.