Many-body excitations in tunneling current spectra of a few-electron quantum dot

TL;DR

This paper investigates how asymmetries and many-body state overlaps influence tunneling currents in few-electron quantum dots, confirming the applicability of single-electron transport theory at high magnetic fields.

Contribution

It highlights the importance of overlap matrix elements and spin rules in accurately describing tunneling spectra in quantum dots under strong magnetic fields.

Findings

Overlap matrix elements are crucial for tunneling descriptions.

Excited (N-1)-electron states are identifiable in transport measurements.

Single-electron quantum transport theory remains valid at high magnetic fields.

Abstract

Inherent asymmetry in the tunneling barriers of few-electron quantum dots induces intrinsically different tunneling currents for forward and reverse source-drain biases in the non-linear transport regime. Here we show that in addition to spin selection rules, overlap matrix elements between many-body states are crucial for the correct description of tunneling transmission through quantum dots at large magnetic fields. Signatures of excited (N-1)-electron states in the transport process through the N-electron system are clearly identified in the measured transconductances. Our analysis clearly confirms the validity of single-electron quantum transport theory in quantum dots.