Spin-polarized zero-bias peak from a single magnetic impurity at an s-wave superconductor: first-principles study

Park, Kyungwha; Nyári, Bendegúz; Lászlóffy, András; Szunyogh, L.; Újfalussy, B.

doi:10.48550/arxiv.2109.05511

Cited by 2 publications

(2 citation statements)

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“…Such zero bias peaks in extended chains are of primary interest nowadays because they are supposed to realize topological quantum bits [25][26][27]. Quite interestingly, theoretical calculations on the same platform as in this work reveal that ZBP's can be formed in single magnetic impurities on top of superconducting Pb(110) by tilting the magnetic orientation of the impurity with respect to the surface [28]. The present calculations demonstrate that ZBP's can be created with the manipulation of the relative angle in dimers.…”

Section: B Mn Dimers On Nb(110)mentioning

confidence: 63%

Relativistic first-principles theory of Yu-Shiba-Rusinov states applied to Mn adatoms and Mn dimers on Nb(110)

et al. 2021

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We present a fully relativistic first-principles-based theoretical approach for the calculation of the spectral properties of magnetic impurities on the surface of a superconducting substrate, providing a material specific framework for the investigation of the Yu-Shiba-Rusinov (YSR) states. By using a suitable orbital decomposition of the local densities of states we discuss in great detail the formation of the YSR states for an Mn adatom and for two kinds of Mn dimers placed on the Nb(110) surface and compare our results to recent experimental findings. In the case of the adatom we find that the spin-orbit coupling slightly shifts some of the YSR peaks and also the local spin polarization on the Nb atoms has marginal effects on their positions. Moreover, by scaling the exchange field on the Mn site we could explain the lack of the d x 2 −y 2 -like YSR state in the spectrum. While our results for a close packed ferromagnetic dimer are in satisfactory agreement with the experimentally observed splitting of the YSR states, in the case of an antiferromagnetic dimer we find that the spin-orbit coupling is not sufficiently large to explain the splitting of the YSR states seen in the experiment. Changing the relative orientation of the magnetic moments in this dimer induces splitting of the YSR states and also shifts their energy, leading even to the formation of a zero bias peak in the case of the deepest YSR state.

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Section: B Mn Dimers On Nb(110)mentioning

confidence: 63%

Relativistic first-principles theory of Yu-Shiba-Rusinov states applied to Mn adatoms and Mn dimers on Nb(110)

et al. 2021

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“…But it has to be emphasized, that the fact that there are states at zero energy at some spiraling angle, does not necessarily mean that MZMs are found. As it has been demonstrated before, even in the case of a single magnetic impurity on the surface of a superconducting host, it is possible to obtain a state at zero energy by imposing a canting angle 37 , even though it is not possible to obtain MZMs for a single impurity. Such states are just YSR states that are shifted as a result of the canting angle.…”

Section: First Principles Based Treatment Of Artificial Spin Chain On...mentioning

confidence: 95%

"In silico" evidence of robust Majorana zero modes in artificial spin chains on superconducting substrates

Újfalussy

Nyári

Lászlóffy

et al. 2023

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We present a first-principles computational approach based on a microscopic relativistic theory of inhomogeneous superconductivity to scrutinize edge states of magnetic chains deposited on the surface of superconductors. Detailed investigations of an iron chain on the top of Au-covered Nb(110) have been carried out with quantitative predictions together with studies of quantities well beyond the reach of experimental capabilities to uniquely identify the topological phase. We confirm that ferromagnetic Fe chains on Au/Nb(110) surface does not support any Majorana Zero Mode (MZM); however, a broad range of spin-spirals can be identified with a robust zero energy state displaying signatures of MZMs. For these spirals, we explore the structure of various superconducting order parameters and the role of spin-orbit coupling. Through additional computational experiments, we provide evidence that MZMs are localized to the boundaries of the topological region of the chain. The robustness of the MZM states is also demonstrated, representing a huge step toward potential experimental realizations.

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Spin-polarized zero-bias peak from a single magnetic impurity at an s-wave superconductor: first-principles study

Cited by 2 publications

References 44 publications

Relativistic first-principles theory of Yu-Shiba-Rusinov states applied to Mn adatoms and Mn dimers on Nb(110)

Relativistic first-principles theory of Yu-Shiba-Rusinov states applied to Mn adatoms and Mn dimers on Nb(110)

"In silico" evidence of robust Majorana zero modes in artificial spin chains on superconducting substrates

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