Ab initio Ultrafast Spin Dynamics in Solids

• URL: http://arxiv.org/abs/2012.08711v3
• Date: Thu, 30 Sep 2021 17:41:32 GMT
• Title: Ab initio Ultrafast Spin Dynamics in Solids
• Authors: Junqing Xu, Adela Habib, Ravishankar Sundararaman, and Yuan Ping
• Abstract summary: We present a first-principles real-time density-matrix approach based on Lindblad dynamics to simulate ultrafast spin dynamics for general solid-state systems. We find that the electron-electron scattering is negligible at room temperature but becomes dominant at low temperatures for spin relaxation in n-type GaAs.
• Score: 0.7874708385247353
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Spin relaxation and decoherence is at the heart of spintronics and spin-based quantum information science. Currently, theoretical approaches that can accurately predict spin relaxation of general solids including necessary scattering pathways and capable for ns to ms simulation time are urgently needed. We present a first-principles real-time density-matrix approach based on Lindblad dynamics to simulate ultrafast spin dynamics for general solid-state systems. Through the complete first-principles descriptions of pump, probe and scattering processes including electron-phonon, electron-impurity and electron-electron scatterings with self-consistent electronic spin-orbit couplings, our method can directly simulate the ultrafast pump-probe measurements for coupled spin and electron dynamics over ns at any temperatures and doping levels. We first apply this method to a prototypical system GaAs and obtain excellent agreement with experiments. We find that the relative contributions of different scattering mechanisms and phonon modes differ considerably between spin and carrier relaxation processes. In sharp contrast to previous work based on model Hamiltonians, we point out that the electron-electron scattering is negligible at room temperature but becomes dominant at low temperatures for spin relaxation in n-type GaAs. We further examine ultrafast dynamics in novel spin-valleytronic materials - monolayer and bilayer WSe2 with realistic defects. We find that spin relaxation is highly sensitive to local symmetry and chemical bonds around defects. Our work provides a predictive computational platform for spin dynamics in solids, which has unprecedented potentials for designing new materials ideal for spintronics and quantum information technology.

Related papers

• Nanoscale engineering and dynamical stabilization of mesoscopic spin textures [0.3770540828119563]
  We demonstrate the ability to harness thermalization to engineer and stabilize structured quantum states in a mesoscopically large ensemble of spins. Specifically, we showcase the capacity to generate, control, stabilize, and read out'shell-like' spin texture with interacting $ 13mathrmC$ nuclear spins in diamond.
  arXiv  Detail & Related papers  (2023-10-09T11:46:53Z)
• Electron-mediated entanglement of two distant macroscopic ferromagnets within a nonequilibrium spintronic device [0.8030359871216614]
  We demonstrate that a current pulse can be harnessed to entangle quantum localized spins of two spatially separated spacersmagnets (FMs) We quantify the mixed-state entanglement generated between the FM layers by tracking the time-evolution of the full density matrix and analyzing the build-up of the mutual logarithmic negativity over time. We propose a current-pump/X-ray-probe'' scheme, utilizing ultrafast X-ray spectroscopy, that can witness nonequilibrium and transient entanglement of the FM layers.
  arXiv  Detail & Related papers  (2022-10-13T00:04:57Z)
• Probing dynamics of a two-dimensional dipolar spin ensemble using single qubit sensor [62.997667081978825]
  We experimentally investigate individual spin dynamics in a two-dimensional ensemble of electron spins on the surface of a diamond crystal. We show that this anomalously slow relaxation rate is due to the presence of strong dynamical disorder. Our work paves the way towards microscopic study and control of quantum thermalization in strongly interacting disordered spin ensembles.
  arXiv  Detail & Related papers  (2022-07-21T18:00:17Z)
• Rapidly enhanced spin polarization injection in an optically pumped spin ratchet [49.1301457567913]
  We report on a strategy to boost the spin injection rate by exploiting electrons that can be rapidly polarized. We demonstrate this in a model system of Nitrogen Vacancy center electrons injecting polarization into a bath of 13C nuclei in diamond. Through a spin-ratchet polarization transfer mechanism, we show boosts in spin injection rates by over two orders of magnitude.
  arXiv  Detail & Related papers  (2021-12-14T08:23:10Z)
• The coherence of quantum dot confined electron- and hole-spin in low external magnetic field [0.0]
  We show for the first time that the spin purity performs complex temporal oscillations. Our studies are essential for the design and optimization of quantum-dot-based entangled multi-photon sources.
  arXiv  Detail & Related papers  (2021-08-11T12:00:30Z)
• Visualizing spinon Fermi surfaces with time-dependent spectroscopy [62.997667081978825]
  We propose applying time-dependent photo-emission spectroscopy, an established tool in solid state systems, in cold atom quantum simulators. We show in exact diagonalization simulations of the one-dimensional $t-J$ model that the spinons start to populate previously unoccupied states in an effective band structure. The dependence of the spectral function on the time after the pump pulse reveals collective interactions among spinons.
  arXiv  Detail & Related papers  (2021-05-27T18:00:02Z)
• Anisotropic electron-nuclear interactions in a rotating quantum spin bath [55.41644538483948]
  Spin-bath interactions are strongly anisotropic, and rapid physical rotation has long been used in solid-state nuclear magnetic resonance. We show that the interaction between electron spins of nitrogen-vacancy centers and a bath of $13$C nuclear spins introduces decoherence into the system. Our findings offer new insights into the use of physical rotation for quantum control with implications for quantum systems having motional and rotational degrees of freedom that are not fixed.
  arXiv  Detail & Related papers  (2021-05-16T06:15:00Z)
• Controlled coherent dynamics of [VO(TPP)], a prototype molecular nuclear qudit with an electronic ancilla [50.002949299918136]
  We show that [VO(TPP)] (vanadyl tetraphenylporphyrinate) is a promising system suitable to implement quantum computation algorithms. It embeds an electronic spin 1/2 coupled through hyperfine interaction to a nuclear spin 7/2, both characterized by remarkable coherence.
  arXiv  Detail & Related papers  (2021-03-15T21:38:41Z)
• Spin-spin interactions in solids from mixed all-electron and pseudopotential calculations $-$ a path to screening materials for spin qubits [1.5119440099674917]
  We present a real-space approach based on density functional theory for the calculation of spin-Hamiltonian parameters. We show that only a small number of atoms surrounding a defect need to be treated at the all-electron level, in order to obtain an overall all-electron accuracy. We also present results for coherence times, computed with the cluster correlation expansion method, highlighting the importance of accurate spin-Hamiltonian parameters for quantitative predictions of spin dynamics.
  arXiv  Detail & Related papers  (2021-01-30T06:22:21Z)
• The limit of spin lifetime in solid-state electronic spins [77.34726150561087]
  We provide a complete first-principles picture of spin relaxation that includes up to two-phonon processes. We study a vanadium-based molecular qubit and reveal that the spin lifetime at high temperature is limited by Raman processes.
  arXiv  Detail & Related papers  (2020-04-08T14:27:36Z)

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.