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arXiv · 2211.04882

Three-carrier spin blockade and coupling in bilayer graphene double quantum dots

Chuyao Tong·Florian Ginzel·Wei Wister Huang·Annika Kurzmann·Rebekka Garreis·Kenji Watanabe·Takashi Taniguchi·Guido Burkard·Jeroen Danon·Thomas Ihn·Klaus Ensslin
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Abstract

The spin degree of freedom is crucial for the understanding of any condensed matter system. Knowledge of spin-mixing mechanisms is not only essential for successful control and manipulation of spin-qubits, but also uncovers fundamental properties of investigated devices and material. For electrostatically-defined bilayer graphene quantum dots, in which recent studies report spin-relaxation times T1 up to 50ms with strong magnetic field dependence, we study spin-blockade phenomena at charge configuration $(1,2)\leftrightarrow(0,3)$. We examine the dependence of the spin-blockade leakage current on interdot tunnel coupling and on the magnitude and orientation of externally applied magnetic field. In out-of-plane magnetic field, the observed zero-field current peak could arise from finite-temperature co-tunneling with the leads; though involvement of additional spin- and valley-mixing mechanisms are necessary for explaining the persistent sharp side peaks observed. In in-plane magnetic field, we observe a zero-field current dip, attributed to the competition between the spin Zeeman effect and the Kane-Mele spin-orbit interaction. Details of the line shape of this current dip however, suggest additional underlying mechanisms are at play.

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Chuyao Tong, Florian Ginzel, Wei Wister Huang, Annika Kurzmann, Rebekka Garreis, Kenji Watanabe, Takashi Taniguchi, Guido Burkard, Jeroen Danon, Thomas Ihn, Klaus Ensslin. 2022-11-09. Three-carrier spin blockade and coupling in bilayer graphene double quantum dots. https://doi.org/10.1103/physrevlett.133.017001

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