Quantum 2025 – wissenschaftliches Programm
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FRI: Friday Contributed Sessions
FRI 12: Quantum Phenomena in Solid-State Devices
FRI 12.4: Vortrag
Freitag, 12. September 2025, 11:30–11:45, ZHG105
Electron-hole quantum dots in bilayer graphene — •Christoph Stampfer1,2, Katrin Hecker1, Lars Mester1, Hubert Dulisch1, Konstantinos Kontogeorgiou3, Simone Sotgiu1, Fabian Hassler3, and Christian Volk1,2 — 1JARA-FIT and 2nd Institute of Physics A, RWTH Aachen University, Aachen, Germany, EU — 2Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Jülich, Germany, EU — 3JARA-Institute for Quantum Information, RWTH Aachen University, 52056 Aachen, Germany, EU
Here we show that bilayer graphene allows the realization of electron-hole double quantum dots that exhibit near-perfect particle-hole symmetry, in which transport occurs via the creation and annihilation of single electron-hole pairs with opposite quantum numbers. We demonstrate that particle-hole symmetric spin and valley textures lead to a protected single-particle spin-valley blockade. The latter will allow robust spin-to-charge and valley-to-charge conversion, which are essential for the operation of spin and valley qubits. By time-resolved measurements where we apply a dual pulse between the (0e, 0h) to (1e, 1h) charge configurations we study unconventional higher order tunneling processes which are able to lift the blockade. Extracting the timescales of blockade lifting and investigating the main mechanisms in the strong lead-quantum dot coupled system, allows us to confirm the state degeneracies. Combined with microwave control, the presented spin-valley blockade will enable the study of spin and valley coherence times by electron spin-resonance or electron dipole spin-resonance techniques, and open the door for spin and valley qubit operation.
Keywords: bilayer graphene; quantum dots; spin qubits; spin-valley blockade