<i>Ab initio</i>
 ultrafast spin dynamics in solids

Xu, Junqing; Habib, Adela; Sundararaman, Ravishankar; Ping, Yuan

doi:10.1103/physrevb.104.184418

Cited by 16 publications

(38 citation statements)

References 94 publications

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“…29,30 We applied this method to disparate materials and obtained good agreement with experiments. 26,29,30 This new method enables us to predict the τ s of silicene and germanene at finite temperatures with realistic interactions with the environment without introducing any simplified model or empirical parameters, for picosecond to microsecond time scale simulation.…”

Section: ■ Introductionmentioning

confidence: 75%

“…The master equation of density matrix ρ( t ) due to e-ph and e-i scattering in interaction picture reads , …”

Section: Methodsmentioning

confidence: 99%

“…Compared with graphene, for which τ s has been extensively studied, ,, the τ s of silicene and germanene have not been measured and the existing few theoretical studies were done based on relatively simple models , without realistic interactions with phonons and impurities. Recently, we developed a first-principles density-matrix (FPDM) method with quantum descriptions of the scattering processes between electron–phonon (e-ph), electron–impurities (e-i), and electron–electron to simulate spin–orbit-mediated spin dynamics in solid-state systems with arbitrary symmetry. , We applied this method to disparate materials and obtained good agreement with experiments. ,, This new method enables us to predict the τ s of silicene and germanene at finite temperatures with realistic interactions with the environment without introducing any simplified model or empirical parameters, for picosecond to microsecond time scale simulation.…”

Section: Introductionmentioning

confidence: 99%

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Giant Spin Lifetime Anisotropy and Spin-Valley Locking in Silicene and Germanene from First-Principles Density-Matrix Dynamics

Takenaka

Habib

et al. 2021

Nano Lett.

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Through first-principles real-time density-matrix (FPDM) dynamics simulations, we investigated spin relaxation due to electron−phonon and electron−impurity scatterings with spin−orbit coupling (SOC) in two-dimensional Dirac materials silicene and germanene at finite temperatures. We discussed the applicability of conventional descriptions of spin relaxation mechanisms by Elliott-Yafet (EY) and D'yakonov-Perel' (DP) compared to the FPDM method, which is determined by a complex interplay of intrinsic SOC, external fields, and scattering strength. For example, the electric field dependence of the spin lifetime by FPDM is close to the DP mechanism for silicene at room temperature but similar to the EY mechanism for germanene. Because of its stronger SOC strength and buckled structure in contrast to graphene, germanene has a giant spin lifetime anisotropy and spin-valley locking effect under nonzero E z and low temperatures. More importantly, germanene has a long spin lifetime (∼100 ns at 50 K) and an ultrahigh carrier mobility, making it advantageous for spin-valleytronic applications.

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Section: ■ Introductionmentioning

confidence: 75%

“…The master equation of density matrix ρ( t ) due to e-ph and e-i scattering in interaction picture reads , …”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Giant Spin Lifetime Anisotropy and Spin-Valley Locking in Silicene and Germanene from First-Principles Density-Matrix Dynamics

Takenaka

Habib

et al. 2021

Nano Lett.

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“…Here, we examine the substrate effects on spin relaxation in Ge through FPDM simulations, with selfconsistent SOC and quantum descriptions of e-ph and e-i scattering processes. [18,19] We study free-standing Ge and Ge supported by four different insulating substrates -germanane (GeH), silicane (SiH), GaTe and InSe. The choice of substrates is based on similar lattice constants to Ge, preservation of Dirac Cones, and experimental synthesis accessibility [20,21].…”

Section: Introductionmentioning

confidence: 99%

Substrate Effects on Spin Relaxation in Two-Dimensional Dirac Materials with Strong Spin-Orbit Coupling

Pan

2022

Preprint

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Understanding substrate effects on spin dynamics and relaxation in two-dimensional (2D) materials is of key importance for spintronics and quantum information applications. However, the key factors that determine the substrate effect on spin relaxation, in particular for materials with strong spin-orbit coupling, have not been well understood. Here we performed first-principles real-time density-matrix dynamics simulations with spin-orbit coupling (SOC) and quantum descriptions of electron-phonon and electron-impurity scattering for the spin lifetimes of supported/free-standing germanene, a prototypical strong SOC 2D Dirac material. We show that the effects of different substrates on spin lifetime can surprisingly differ by two orders of magnitude. We find that such huge difference seems to be mostly caused by substrate-induced modifications of spin-flip scattering matrix elements, in sharp contrast to the substrate effects on weak SOC materials like graphene.

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“…Previous work has identified two key sources of phononinduced spin decoherence in the presence of spin-orbit coupling (SOC) − the Elliott-Yafet (EY) mechanism 5,6 , whereby electron-phonon (e-ph) collisions change the spin direction, and the Dyakonov-Perel (DP) mechanism 7 originating from spin precession between e-ph collisions. Historically, these two mechanisms have been described with distinct theoretical models [5][6][7]21,22 , although significant efforts have been made to unify them, for example using real-time evolution of spin ensembles [23][24][25] or analyzing quasiparticle broadening in model systems [26][27][28] .…”

mentioning

confidence: 99%

Predicting electron spin decoherence with a many-body first-principles approach

Park¹,

Zhou²,

Luo³

et al. 2022

Preprint

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Developing a microscopic understanding of spin decoherence is essential to advancing quantum technologies [1][2][3][4] . Electron spin decoherence due to atomic vibrations (phonons) plays a special role as it sets an intrinsic limit to the performance of spin-based quantum devices. Two main sources of phonon-induced spin decoherence -the Elliott-Yafet (EY) and Dyakonov-Perel (DP) mechanismshave distinct physical origins and theoretical treatments 5-7 . Here we show calculations that unify their modeling and enable accurate predictions of spin relaxation and precession in semiconductors. We compute the phonon-dressed vertex of the spin-spin correlation function, with a treatment analogous to the calculation of the anomalous electron magnetic moment in QED 8 . We find that the vertex correction provides a giant renormalization of the electron spin dynamics in solids, greater by many orders of magnitude than the corresponding correction in vacuum. Our work demonstrates a general approach for quantitative analysis of spin decoherence in materials, advancing the quest for spin-based quantum technologies.

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Ab initio ultrafast spin dynamics in solids

Cited by 16 publications

References 94 publications

Giant Spin Lifetime Anisotropy and Spin-Valley Locking in Silicene and Germanene from First-Principles Density-Matrix Dynamics

Giant Spin Lifetime Anisotropy and Spin-Valley Locking in Silicene and Germanene from First-Principles Density-Matrix Dynamics

Substrate Effects on Spin Relaxation in Two-Dimensional Dirac Materials with Strong Spin-Orbit Coupling

Predicting electron spin decoherence with a many-body first-principles approach

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