Superluminal Propagation of Composite Collective Modes in Superconductor-Ferromagnet Heterostructures

• URL: http://arxiv.org/abs/2407.05457v2
• Date: Thu, 3 Oct 2024 12:09:21 GMT
• Title: Superluminal Propagation of Composite Collective Modes in Superconductor-Ferromagnet Heterostructures
• Authors: Pascal Derendorf, Anatoly F. Volkov, Ilya M. Eremin,
• Abstract summary: We show that the spectrum of composite collective modes, $omega(k)$, has a qualitatively different form in the case of $H_demH_an$ and of $H_dem>H_an$. For moderate or weak anisotropy in ferromagnet the group velocity of collective modes demonstrates inflection point where the group velocity become infinite and is superluminal.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Superconductor/ferromagnet/superconductor Josephson junctions are paradigmatic systems for studying the delicate interplay of superconductivity and magnetism via proximity effects as well as their composite excitations. Here, we analyse the collective modes (CM) in such a heterostructure by taking into account the interplay between the de-magnetisation field $H_{dem}$ and the field caused by the anisotropy of the ferromagnet $H_{an}$, which was previously neglected. It turns out that the spectrum of composite collective modes, $\omega(k)$, has a qualitatively different form in the case of $H_{dem}<H_{an}$ and of $H_{dem}>H_{an}$. In the first case, the dependence $\omega(k)$ has the same form as in previous studies, whereas in the second case, the spectrum looks completely different. In particular, for moderate or weak anisotropy in ferromagnet the group velocity of collective modes demonstrates inflection point where the group velocity become infinite and is superluminal. Furthermore, this point separates purely real and complex-conjugate solutions for the collective modes and is also {\it exception point}. We show that the difference of the CMs spectra can be revealed by Fiske experiment, i.\,e.\,by measuring the $I-V$ characteristics in the presence of magnetic field and voltage.

Related papers

• Zeeman polaritons as a platform for probing Dicke physics in condensed matter [2.523996579776851]
  We show that a spin--boson system is more compatible with the Dicke model and has advantages over boson--boson systems for pursuing experimental realizations of phenomena predicted for ultrastrongly coupled light--matter hybrids. This finding demonstrates that a spin--boson system is more compatible with the Dicke model and has advantages over boson--boson systems for pursuing experimental realizations of phenomena predicted for ultrastrongly coupled light--matter hybrids.
  arXiv  Detail & Related papers  (2024-09-25T20:28:01Z)
• Ancilla quantum measurements on interacting chains: Sensitivity of entanglement dynamics to the type and concentration of detectors [46.76612530830571]
  We consider a quantum many-body lattice system that is coupled to ancillary degrees of freedom (detectors'') We explore the dynamics of density and of entanglement entropy in the chain, for various values of $rho_a$ and $M$.
  arXiv  Detail & Related papers  (2023-11-21T21:41:11Z)
• Fragmented superconductivity in the Hubbard model as solitons in Ginzburg-Landau theory [58.720142291102135]
  Superconductivity and charge density waves are observed in close vicinity in strongly correlated materials. We investigate the nature of such an intertwined state of matter stabilized in the phase diagram of the elementary $t$-$tprime$-$U$ Hubbard model. We provide conclusive evidence that the macroscopic wave functions of the superconducting fragments are well-described by soliton solutions of a Ginzburg-Landau equation.
  arXiv  Detail & Related papers  (2023-07-21T18:00:07Z)
• Cavity-mediated superconductor$\unicode{x2013}$ferromagnetic insulator coupling [0.0]
  A proof of concept showed that cavity photons can mediate a ferromagnetic (FI) signature over a distance insulator. We show that an arbitrary field of $14 isotropyIG induced an arbitrary tilt of the FI. We discuss the implications and potential applications of such superconducting spintronics.
  arXiv  Detail & Related papers  (2022-09-19T19:05:38Z)
• Understanding the propagation of excitations in quantum spin chains with different kind of interactions [68.8204255655161]
  It is shown that the inhomogeneous chains are able to transfer excitations with near perfect fidelity. It is shown that both designed chains have in common a partially ordered spectrum and well localized eigenvectors.
  arXiv  Detail & Related papers  (2021-12-31T15:09:48Z)
• Enhanced superconductivity and various edge modes in modulated $t$-$J$ chains [6.0413288393037305]
  We numerically investigate the ground state of the extended $t$-$J$ Hamiltonian with periodic local modulations in one dimension. We obtain a rich ground-state phase diagram consisting of the metallic state, the superconducting state, the phase separation, and insulating states at commensurate fillings.
  arXiv  Detail & Related papers  (2021-11-26T19:00:18Z)
• Dispersive readout of molecular spin qudits [68.8204255655161]
  We study the physics of a magnetic molecule described by a "giant" spin with multiple $d > 2$ spin states. We derive an expression for the output modes in the dispersive regime of operation. We find that the measurement of the cavity transmission allows to uniquely determine the spin state of the qudits.
  arXiv  Detail & Related papers  (2021-09-29T18:00:09Z)
• Quartic metal: Spontaneous breaking of time-reversal symmetry due to four-fermion correlations in Ba$_{1-x}$K$_x$Fe$_2$As$_2$ [3.076082310544129]
  Superconducting states are a spontaneously broken symmetry corresponding to long-range coherence of fermion pairs. We show that the formation of fermionic bound states leads to spontaneous breaking of time-reversal symmetry above the superconducting transition temperature.
  arXiv  Detail & Related papers  (2021-03-31T16:19:42Z)
• Photon Condensation and Enhanced Magnetism in Cavity QED [68.8204255655161]
  A system of magnetic molecules coupled to microwave cavities undergoes the equilibrium superradiant phase transition. The effect of the coupling is first illustrated by the vacuum-induced ferromagnetic order in a quantum Ising model. A transmission experiment is shown to resolve the transition, measuring the quantum electrodynamical control of magnetism.
  arXiv  Detail & Related papers  (2020-11-07T11:18:24Z)
• Site Mixing for Engineering Magnetic Topological Insulators [8.820630220432209]
  The impact of antisite defects on magnetism and electronic structure is studied in MnSb$$Te$_4$. The detailed nonstoichiometry and site mixing of MnSb-$Te$_4$ crystals depend on the growth parameters.
  arXiv  Detail & Related papers  (2020-07-23T19:08:36Z)
• Optimal coupling of HoW$_{10}$ molecular magnets to superconducting circuits near spin clock transitions [85.83811987257297]
  We study the coupling of pure and magnetically diluted crystals of HoW$_10$ magnetic clusters to microwave superconducting coplanar waveguides. Results show that engineering spin-clock states of molecular systems offers a promising strategy to combine sizeable spin-photon interactions with a sufficient isolation from unwanted magnetic noise sources.
  arXiv  Detail & Related papers  (2019-11-18T11:03:06Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.