Regensburg 2022 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 13: Quantum Dots, Quantum Wires, Point Contacts

TT 13.1: Talk

Tuesday, September 6, 2022, 09:30–09:45, H23

Precession of entangled spin and pseudospin in double quantum dots — •Christoph Rohrmeier and Andrea Donarini — University Regensburg

Quantum dot spin valves are characterized by exchange fields [1] which induce spin precession and generate anomalous spin resonances [2]. Analogous effects have been studied in double quantum dots, in which the orbital degree of freedom replaces the role of the spin in the valve configuration [3]. We generalize, now, this setup to allow for arbitrary spin and orbital polarization of the leads, thus obtaining an even richer variety of current resonances, stemming from the entangled precession dynamics of the spin and pseudospin [4]. We observe for both vectors a delicate interplay of decoherence, pumping and precession which can only be understood by including the dynamics of the spin-pseudospin correlators. The results are obtained in the framework of a generalized master equation within the cotunneling approximation and are complemented by a coherent sequential tunneling model.

[1] Braun et al., Phys. Rev. B 70 (2004) 195345

[2] Hell et al., Phys. Rev. B 91 (2015) 195404

[3] Rohrmeier et al., Phys. Rev. B 103 (2021) 205420

[4] Rohrmeier et al., Phys. Rev. B 105 (2022) 205418