Spin-blockade spectroscopy of a two-level artificial molecule.

Area of Science:

• Quantum dots and molecular electronics
• Spin physics and spintronics
• Spectroscopy techniques

Background:

• Coulomb and spin blockade are quantum phenomena crucial for understanding electron transport in nanoscale devices.
• Artificial molecules, fabricated using electrostatic gates, serve as model systems for studying quantum phenomena.
• Spin-polarized leads are essential for probing the spin-dependent electronic properties of quantum systems.

Purpose of the Study:

• To investigate the electronic spin states of a two-level artificial molecule using Coulomb- and spin-blockade spectroscopy.
• To explore the influence of magnetic fields on the tunnel coupling within the artificial molecule.
• To understand the role of device geometry in observed quantum phenomena.

Main Methods:

• Fabrication of an electrostatically defined artificial molecule.
• Utilizing spin-polarized leads for electron injection and detection.
• Performing Coulomb- and spin-blockade spectroscopy measurements.
• Applying magnetic fields to probe spin-dependent transport characteristics.

Main Results:

• Successfully reduced the artificial molecule to a two-level system.
• Identified the electronic spin states of the molecule via spin-sensitive conductance.
• Observed magnetic-field-induced modulations in the inter-atomic tunnel coupling.
• Correlated the observed phenomena with the lateral geometry of the device.

Conclusions:

• Coulomb- and spin-blockade spectroscopy are effective tools for characterizing spin states in artificial molecules.
• Magnetic fields can dynamically tune quantum interactions, such as tunnel coupling, in molecular systems.
• The lateral device architecture plays a significant role in mediating spin-dependent transport and coupling effects.