QDLQuantum Device LabJeonbuk National University
Research

Coherence. Interactions.
Quantum control.

We use tunable nanoscale devices to ask how electrons behave as waves, how they interact, and how their quantum states can be measured and controlled.

Four connected themes

How do electrons reveal
their quantum nature?

We study coherence and interactions in controllable electronic systems. Each theme connects a physical question to a device platform and a measurement strategy.

01 Coherence · Interference

Electron Quantum Optics

PlatformQuantum Hall interferometersInterference · dephasing · path information

Electrons behave as coherent matter waves. Using Mach–Zehnder and Fabry–Pérot interferometers in the quantum Hall regime, we investigate how path information and Coulomb interactions change their interference.

Key questions

  • How does which-path information suppress—and erase—electronic interference?
  • How do interactions modify phase, effective charge, and the area of a quantum Hall interferometer?
Representative work

Controlled Dephasing of an Electron Interferometer · PRL 109, 250401 (2012)

An electronic quantum eraser · Science 344, 1363 (2014)

Robust electron pairing in the integer quantum Hall effect regime · Nature Communications 6, 7435 (2015)

02 Entropy · Correlations

Quantum Dot Thermodynamics & Many-Body Physics

PlatformCoupled semiconductor quantum dotsCharge sensing · thermometry · entropy

Quantum dots let us control charge occupation and coupling one electron at a time. We use charge sensing and precision thermometry to investigate how microscopic states and many-body correlations appear in thermodynamic observables.

Key questions

  • How do degeneracy and coupling alter the entropy of few-electron systems?
  • How can many-body correlations be identified through thermodynamic measurements?
Representative work & current direction

Charge Frustration in a Triangular Triple Quantum Dot · PRL 110, 046803 (2013)

Strong electron-occupancy dependence of the lever arm · JKPS 87, 67 (2025)

Direct entropy measurements in coupled quantum dots · Ongoing research

03 Modes · Energy relaxation

Coherent Electron Dynamics

PlatformOpen cavities & electron emittersMagnetic focusing · transport · energy relaxation

How does an electron travel through a device before losing its coherence or energy? Open cavities, magnetic focusing, and quantum-dot emitters let us investigate spatial modes, coherent propagation, and energy relaxation.

Key questions

  • Which electronic modes survive in an open, phase-coherent cavity?
  • How do injected hot electrons relax as they travel through a two-dimensional electron gas?
Representative work

Significant energy relaxation of quantum dot emitted hot electrons · PR Research 3, 033015 (2021)

Observation of Electronic Modes in Open Cavity Resonator · Nature Communications 14, 415 (2023)

Channel-resolved wavefunctions of transverse magnetic focusing · Communications Physics 7, 418 (2024)

04 Graphene · Quantum confinementDeveloping platform

Graphene Quantum Dots

PlatformGraphene / hBN heterostructuresDevice fabrication · electrical control

We are developing graphene quantum dots and van der Waals heterostructure devices for controlled quantum transport. This ongoing direction focuses on reproducible fabrication, charge confinement, and tunable tunnel coupling.

Key questions

  • How do confinement, edge structure, and disorder shape electronic states in graphene quantum dots?
  • How can charge occupation and tunnel coupling be controlled reproducibly in graphene-based devices?
Current research directions

Graphene quantum dots with tunable charge confinement · Ongoing research

Graphene/hBN heterostructure quantum-device fabrication · Ongoing research

Low-temperature transport and charge-state control · Ongoing research