3 research outputs found
Quantum spins and hybridization in artificially-constructed chains of magnetic adatoms on a superconductor
Magnetic adatom chains on surfaces constitute fascinating quantum spin
systems. Superconducting substrates suppress interactions with bulk electronic
excitations but couple the adatom spins to a chain of subgap Yu-Shiba-Rusinov
(YSR) quasiparticles. Using a scanning tunneling microscope, we investigate
such correlated spin-fermion systems by constructing Fe chains adatom by adatom
on superconducting NbSe. The adatoms couple entirely via the substrate,
retaining their quantum spin nature. In dimers, we observe that the deepest YSR
state undergoes a quantum phase transition due to Ruderman-Kittel-Kasuya-Yosida
interactions, a distinct signature of quantum spins. Chains exhibit coherent
hybridization and band formation of the YSR excitations, indicating
ferromagnetic coupling. Longer chains develop separate domains due to
coexisting charge-density-wave order of NbSe. Despite the
spin-orbit-coupled substrate, we find no signatures of Majoranas, possibly
because quantum spins reduce the parameter range for topological
superconductivity. We suggest that adatom chains are versatile systems for
investigating correlated-electron physics and its interplay with topological
superconductivity
Original experimental data and code for the Paper ”Quantum spins and hybridization in artificially-constructed chains of magnetic adatoms on a superconductor“
Magnetic adatom chains on surfaces constitute fascinating quantum spin systems. Superconducting substrates suppress interactions with bulk electronic excitations but couple the adatom spins to a chain of subgap Yu-Shiba-Rusinov (YSR) quasiparticles. Using a scanning tunneling microscope, we investigate such correlated spin-fermion systems by constructing Fe chains adatom by adatom on superconducting NbSe2. The adatoms couple entirely via the substrate, retaining their quantum spin nature. In dimers, we observe that the deepest YSR state undergoes a quantum phase transition due to Ruderman-Kittel-Kasuya-Yosida interactions, a distinct signature of quantum spins. Chains exhibit coherent hybridization and band formation of the YSR excitations, indicating ferromagnetic coupling. Longer chains develop separate domains due to coexisting charge-density-wave order of NbSe2. Despite the spin-orbit-coupled substrate, we find no signatures of Majoranas, possibly because quantum spins reduce the parameter range for topological superconductivity. We suggest that adatom chains are versatile systems for investigating correlated-electron physics and its interplay with topological superconductivity
Quantum spins and hybridization in artificially-constructed chains of magnetic adatoms on a superconductor
Magnetic adatom chains on surfaces constitute fascinating quantum spin systems. Superconducting substrates suppress interactions with bulk electronic excitations but couple the adatom spins to a chain of subgap Yu-Shiba-Rusinov (YSR) quasiparticles. Using a scanning tunneling microscope, we investigate such correlated spin-fermion systems by constructing Fe chains adatom by adatom on superconducting NbSe. The adatoms couple entirely via the substrate, retaining their quantum spin nature. In dimers, we observe that the deepest YSR state undergoes a quantum phase transition due to Ruderman-Kittel-Kasuya-Yosida interactions, a distinct signature of quantum spins. Chains exhibit coherent hybridization and band formation of the YSR excitations, indicating ferromagnetic coupling. Longer chains develop separate domains due to coexisting charge-density-wave order of NbSe. Despite the spin-orbit-coupled substrate, we find no signatures of Majoranas, possibly because quantum spins reduce the parameter range for topological superconductivity. We suggest that adatom chains are versatile systems for investigating correlated-electron physics and its interplay with topological superconductivity