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HL: Fachverband Halbleiterphysik
HL 38: Materials and Devices for Quantum Technology II
HL 38.6: Vortrag
Donnerstag, 12. März 2026, 10:45–11:00, POT/0051
Hexagonal Germanium Nanowires as a Spin Qubit Platform — •Anirban Das1, Baksa Kolok1,2, Daniel Varjas1,3, and Andras Palyi1,2 — 1Department of Theoretical Physics, BME, Budapest, Hungary — 2HUN-REN-BME-BCE QTRG, BME, Budapest, Hungary — 3IFW Dresden and Würzburg-Dresden Cluster of Excellence ct.qmat, Dresden, Germany
Hexagonal germanium (2H-Ge) offers strong spin-orbit interaction and optical activity, making it an appealing platform for semiconductor spin qubits. Recent progress in growing hexagonal SixGe1−x nanowires enables controlled geometries suitable for quantum devices. In contrast to cubic Si or Ge, 2H-Ge supports direct band-gap transitions, opening a pathway towards a novel spin-photon interface.
We study the electronic and spin properties of 2H-Ge nanowires using a multiband k·p Hamiltonian describing low-energy states near the Γ point. By discretizing the model with open boundaries, we construct nanowires oriented perpendicular to the c-axis and compute their band structure. We analyze confinement-induced gap variations and the influence of transverse electric fields, from which we extract Rashba coefficients. Magnetic fields are included via a Peierls substitution to investigate anisotropic spin responses. The resulting effective g-tensor shows strong directional dependence, revealing regimes favorable for qubit operation in hexagonal Ge nanowires.
This research is supported by the European Union within the Horizon Europe research and innovation programme via the ONCHIPS project under grant agreement No 101080022.
Keywords: Spin qubit; Hexagonal Germanium; Nanowire; g-factor; Rashba SOC