Evidence for spin-dependent energy transport in a superconductor

Kuzmanović, Marko; Wu, Bi; Weideneder, M.; Quay, C. H. L.; Aprili, M.

doi:10.1038/s41467-020-18161-w

Cited by 9 publications

(8 citation statements)

References 42 publications

(57 reference statements)

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“…Since the transported energy current is a sum of kinetic and mass (i.e., excitation) energy but not potential energy [109]. The above interpretation of the role of quasiparticle states is consistent with recent experimental evidence for a non-vanishing quasiparticle population during spin dependent transport of energy in a superconductor [110]. Thus, the presence of such broken symmetry state has crucial effects on energy interconversion with HPM-based QDs.…”

Section: Implications Of a Bias-dependent Particle-hole Asymmetrysupporting

confidence: 72%

Kondo resonance effects in emergent flat band materials

Ukpong

2023

Front. Phys.

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Macroscopic degrees of freedom that are involved in the transport of carriers through mesoscopic electronic devices are susceptible to the effects of strong many-body correlations. The presence of magnetic impurities in dilute magnetic alloys typically allow for insights into Kondo effect from the scattering of free carriers by localized electron states of the magnetic impurities but this effect is not well understood when there are no d-band electron states. Herein, the signatures of Kondo resonance effect are elucidated in quantum dots derived from a carbon-nanoline embedded monolayer hexagonal boron nitride whose electron states host flat band ferromagnetism as distinct broken symmetry states. Quantum transport state of mesoscopic devices modelled as quantum dots tunnel coupled to metallic leads is computed by direct diagonalization of the Hamiltonian. The possibility of realizing quantum dots with highly tunable electron states in energy interconversion devices is discussed to show the importance of screening effects on single-electron energy levels. The quantum master equation is solved within different formalisms to determine the stationary-state particle and energy currents. Stability diagrams are calculated to show the dependence of the conductance on experimental control variables of the quantum dot device. The computed responses of the stationary-state transport signatures are used to characterize Kondo resonance effects from flat band states of embedded carbon nanoline-based quantum dots. It is found that the local network structure of the hexagonal ring carbon cluster-based quantum dot has a broken particle-hole symmetry in the transport state. This signals the formation of the quasiparticle states expected in second order scattering when the macroscopic “charge” pseudospin symmetry of the tunnelling electron state is broken dynamically due to charging. The results are discussed to show the implications of a vanishing particle-hole symmetry in the carrier transport state of quantum dots for energy conversion applications.

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Section: Implications Of a Bias-dependent Particle-hole Asymmetrysupporting

confidence: 72%

Kondo resonance effects in emergent flat band materials

Ukpong

2023

Front. Phys.

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“…Recently it has been discovered [12][13][14][15][16][17] that superconductivity strongly increases spin relaxation times and lengths, which makes superconducting materials promising for spintronics [18][19][20]. Long-range nonequilibrium spin states created in superconductors by electrical and thermal injection of Bogoliubov quasiparticles have been intensively studied [20][21][22][23][24][25][26][27][28]. The question of how the weak spin relaxation in superconductors shows up in spin pumping properties have remained unexplored and is addressed in the present paper.…”

mentioning

confidence: 94%

Giant enhancement to spin battery effect in superconductor/ferromagnetic insulator systems

et al. 2021

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We develop a theory of the spin battery effect in superconductor/ferromagnetic insulator (SC/FI) systems taking into account the magnetic proximity effect. We demonstrate that the spin-energy mixing enabled by the superconductivity leads to the enhancement of spin accumulation by several orders of magnitude relative to the normal state. This finding can explain the recently observed giant inverse spin Hall effect generated by thermal magnons in the SC/FI system. We suggest a nonlocal electrical detection scheme which can directly probe the spin accumulation driven by the magnetization dynamics. We predict a giant Seebeck effect converting the magnon temperature bias into the nonlocal voltage signal. We also show how this can be used to enhance the sensitivity of magnon detection even up to the single-magnon level.

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“…Recently it has been discovered [12][13][14][15][16][17] that superconductivity strongly increases spin relaxation times and lengths, which makes superconducting materials promising for spintronics [18][19][20]. Long-range non-equilibrium spin states created in superconductors by electrical and thermal injection of Bogoliubov quasiparticles have been intensively studied [20][21][22][23][24][25][26][27][28]. The question of how the weak spin relaxation in superconductors shows up in spin pumping properties have remained unexplored and is addressed in the present Letter.…”

mentioning

confidence: 99%

Superconductivity provides a giant enhancement to the spin battery effect

Ojajärvi,

Heikkilä,

Virtanen

et al. 2021

Preprint

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We develop a theory of the spin battery effect in superconductor/ferromagnetic insulator (SC/FI) systems taking into account the magnetic proximity effect. We demonstrate that the spin-energy mixing enabled by the superconductivity leads to the enhancement of spin accumulation by several orders of magnitude relative to the normal state. This finding can explain the recently observed giant inverse spin Hall effect generated by thermal magnons in the SC/FI system. We suggest a non-local electrical detection scheme which can directly probe the spin accumulation driven by the magnetization dynamics. We predict a giant Seebeck effect converting the magnon temperature bias into the non-local voltage signal. We also show how this can be used to enhance the sensitivity of magnon detection even up to the single-magnon level.

show abstract

Evidence for spin-dependent energy transport in a superconductor

Cited by 9 publications

References 42 publications

Kondo resonance effects in emergent flat band materials

Kondo resonance effects in emergent flat band materials

Giant enhancement to spin battery effect in superconductor/ferromagnetic insulator systems

Superconductivity provides a giant enhancement to the spin battery effect

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