The angular- and crystal-momentum transfer through electron–phonon coupling in silicon and silicon-carbide: similarities and differences

Miedema, Piter S.; Beye, Martin; Schiwietz, G.; Föhlisch, Alexander

doi:10.1088/1367-2630/16/9/093056

Cited by 5 publications

(4 citation statements)

References 63 publications

(84 reference statements)

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“…We established previously in semiconductors how the angular momentum transfer scattering rate R ( T ) can be deduced from the evolution of valence to core-hole decay peaks with temperature 23,24 as:where τ core − hole is the core-hole lifetime of the excited state, A inc = A cold − A hot (purple hatched area in Fig. 2(a)) is the fraction of decay modified by electron-phonon scattering and A coh = A cold is the fraction not affected by this.…”

Section: Discussionmentioning

confidence: 97%

“…The former is caused by lattice distortions due to the core excited state. The latter is proportional to the phonon population and thus, to the Bose-Einstein distribution 24 . Therefore, the evolution of the electron-phonon transfer rate with temperature can be written as:where C indep and C dep correspond to the temperature independent and the temperature dependent contribution, respectively, and are used as fitting parameters.…”

Section: Discussionmentioning

confidence: 99%

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Measuring the atomic spin-flip scattering rate by x-ray emission spectroscopy

Decker

Born

Büchner

et al. 2019

Sci Rep

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While extensive work has been dedicated to the measurement of the demagnetization time following an ultra-short laser pulse, experimental studies of its underlying microscopic mechanisms are still scarce. In transition metal ferromagnets, one of the main mechanism is the spin-flip of conduction electrons driven by electron-phonon scattering. Here, we present an original experimental method to monitor the electron-phonon mediated spin-flip scattering rate in nickel through the stringent atomic symmetry selection rules of x-ray emission spectroscopy. Increasing the phonon population leads to a waning of the 3 d → 2 p 3/2 decay peak intensity, which reflects an increase of the angular momentum transfer scattering rate attributed to spin-flip. We find a spin relaxation time scale in the order of 50 fs in the 3 d -band of nickel at room temperature, while consistantly, no such peak evolution is observed for the diamagnetic counterexample copper, using the same method.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Measuring the atomic spin-flip scattering rate by x-ray emission spectroscopy

Decker

Born

Büchner

et al. 2019

Sci Rep

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“…This is due to the well-defined symmetry and local nature of the x-ray addressed core states, whereas optical processes target valence transitions, often involving strongly hybridised states with mixed character. Nevertheless, x-ray excitation is a rather strong distortion of the system and subsequent vibrational coupling enables dipole forbidden electronic transitions [32,33].…”

Section: X-ray/optical Sum-frequency Generationmentioning

confidence: 99%

Non-linear soft x-ray methods on solids with MUSIX—the multi-dimensional spectroscopy and inelastic x-ray scattering endstation

Beye

Engel

Schunck

et al. 2018

J. Phys.: Condens. Matter

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With the intense and coherent x-ray pulses available from free-electron lasers, the possibility to transfer non-linear spectroscopic methods from the laser lab to the x-ray world arises. Advantages especially regarding selectivity and thus information content as well as an improvement of signal levels are expected. The use of coherences is especially fruitful and the example of coherent x-ray/optical sum-frequency generation is discussed. However, many non-linear x-ray methods still await discovery, partially due to the necessity for extremely adaptable and versatile instrumentation that can be brought to free-electron lasers for the analysis of the spectral content emitted from the sample into a continuous range of emission angles. Such an instrument (called MUSIX) is being developed and employed at FLASH, the free-electron laser in Hamburg and is described in this contribution together with first results.

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“…Here, we present the experimental determination of the el-ph scattering rates at the nickel and iron atoms in the two different alloys Fe 20 Ni 80 and Fe 50 Ni 50 as well as in pure nickel. Our method is based on the core-hole clock method, where the core-hole lifetime is used as a time reference to deduce the timescale of dynamic processes like the el-ph scattering timescale [23][24][25][26][27][28][29][30] . Following the stringent dipole selection rules, scattered electrons do not participate to the core-hole decay in the case of e.g.…”

mentioning

confidence: 99%

Thresholding of the Elliott-Yafet spin-flip scattering in multi-sublattice magnets by the respective exchange energies

Born

Decker

Büchner

et al. 2021

Sci Rep

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How different microscopic mechanisms of ultrafast spin dynamics coexist and interplay is not only relevant for the development of spintronics but also for the thorough description of physical systems out-of-equilibrium. In pure crystalline ferromagnets, one of the main microscopic mechanism of spin relaxation is the electron-phonon (el-ph) driven spin-flip, or Elliott-Yafet, scattering. Unexpectedly, recent experiments with ferro- and ferrimagnetic alloys have shown different dynamics for the different sublattices. These distinct sublattice dynamics are contradictory to the Elliott-Yafet scenario. In order to rationalize this discrepancy, it has been proposed that the intra- and intersublattice exchange interaction energies must be considered in the microscopic demagnetization mechanism, too. Here, using a temperature-dependent x-ray emission spectroscopy (XES) method, we address experimentally the element specific el-ph angular momentum transfer rates, responsible for the spin-flips in the respective (sub)lattices of Fe$$_{20}$$ 20 Ni$$_{80}$$ 80 , Fe$$_{50}$$ 50 Ni$$_{50}$$ 50 and pure nickel single crystals. We establish how the deduced rate evolution with the temperature is linked to the exchange coupling constants reported for different alloy stoichiometries and how sublattice exchange energies threshold the related el-ph spin-flip channels. Thus, these results evidence that the Elliott-Yafet spin-flip scattering, thresholded by sublattice exchange energies, is the relevant microscopic process to describe sublattice dynamics in alloys and elemental magnetic systems.

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The angular- and crystal-momentum transfer through electron–phonon coupling in silicon and silicon-carbide: similarities and differences

Cited by 5 publications

References 63 publications

Measuring the atomic spin-flip scattering rate by x-ray emission spectroscopy

Measuring the atomic spin-flip scattering rate by x-ray emission spectroscopy

Non-linear soft x-ray methods on solids with MUSIX—the multi-dimensional spectroscopy and inelastic x-ray scattering endstation

Thresholding of the Elliott-Yafet spin-flip scattering in multi-sublattice magnets by the respective exchange energies

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