Longitudinal wave function control in single quantum dots with an applied magnetic field

TL;DR

This paper demonstrates a novel method for controlling the longitudinal wave functions of electrons and holes in single quantum dots using an applied magnetic field, enabling new ways to tune charge distribution and electron-hole interactions.

Contribution

It introduces a new approach to manipulate wave functions along the quantum dot axis with magnetic fields, expanding control capabilities beyond transverse tuning.

Findings

Hole wave function shrinks in the base plane under magnetic field.

Permanent dipole moment and electron-hole alignment can be inverted.

Wave function control affects electron-hole interaction tuning.

Abstract

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots.