연사: Stephen R. McMillan from DIPC CFM

일시: 2026년 09월 23일, 11:00am – 12:00pm

장소: 연구협력관 B1 Jupiter 세미나룸

초록: Steady-state electrical transport can reveal spin interactions without resonant excitation.

For example, transport signatures of non-equilibrium spin precession have been observed in quantum-dot spin valves [1], while spin-dependent recombination in weak static magnetic fields provides access to the microscopic environments of semiconducting defects [2]. 

Spin-polarized current can also establish non-equilibrium spin polarization, providing a route to electrical state preparation [3,4].
Transport bottlenecks provide a common mechanism for dc spin spectroscopy and electrical state preparation. 

At level crossings, spin-selective transport can preferentially populate coherent spin superpositions with suppressed hopping to a magnetic contact, reducing the current and establishing a polarized, generally mixed steady state. 

For a spin- 1/2 center exchange coupled to a nearby spin and probed by spin-polarized STM, magnetoresistance resonances are predicted when the Zeeman energy matches the exchange coupling strength [3]. 

These resonances can remain observable even when the thermal energy exceeds the interaction scale, providing access to weak local couplings.

For spin-1 centers, signatures of zero-field splitting and defect orientation are predicted, offering a means to distinguish different defect configurations and probe their magnetic anisotropy [4].

[1] A. D. Crisan et al. Nat. Commun. 7, 10451 (2016).

[2] E. B. Frantz et al. J. Appl, Phys. 128, 124504 (2020).

[3] S. R. McMillan et al. Phys. Rev. Lett. 125, 257203 (2020).

[4] S. R. McMillan and M. E. Flatté, arXiv:2112.14805 (2021)