Effect of exchange coupling on coherently controlled spin-dependent transition rates

Gliesche, A.; Michel, C.; Rajevac, V.; Lips, K.; Baranovskiǐ, S. D.; Gebhard, Florian; Boehme, Christoph

doi:10.1103/physrevb.77.245206

Cited by 31 publications

(64 citation statements)

References 12 publications

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“…The interface defect signals are weak in spite of the presence of a significantly higher interface defect density compared to the areal density of 31 P close to the interface. This may be explained by considering the signal from interface defect pairs, which have almost identical g-factors and therefore stronger coupling, leading to lower pEDMR signals than those seen from 31 P -defect pairs which have quite different g-factors and weaker, but still finite, coupling 42 , and therefore dominate the signal.…”

Section: Discussionmentioning

confidence: 99%

“…One approach to an understanding of whether the observed g-factors belong to the same or different transitions is to analyze the dynamics of the spin-dependent processes associated with these different resonances: Spin-selection rules usually discriminate permutation symmetries of spin s = 1 2 pairs 40,42 which means that it is the mutual orientation of the two spins, not the individual spin state of one of the two pair partners, which determines the transition rate. Therefore, the transient behavior of spin-dependent transition rates exhibits an identical behavior after a spin resonant manipulation of either one of the two pair partners.…”

Section: Experimental Datamentioning

confidence: 99%

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T1andT2spin relaxation time limitations of phosphorous donor electrons near crystalline silicon to silicon dioxide interface defects

et al. 2010

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A study of donor electron spins and spin-dependent electronic transitions involving phosphorous ( 31 P) atoms in proximity of the (111) oriented crystalline silicon (c-Si) to silicon dioxide (SiO 2 ) interface is presented for [ 31 P] = 10 15 cm −3 and [ 31 P] = 10 16 cm −3 at about liquid 4 He temperatures (T = 5 K − 15 K). Using pulsed electrically detected magnetic resonance (pEDMR), spin-dependent transitions between the 31 P donor state and two distinguishable interface states are observed, namely (i) P b centers which can be identified by their characteristic anisotropy and (ii) a more isotropic center which is attributed to E ′ defects of the SiO 2 bulk close to the interface. Correlation measurements of the dynamics of spin-dependent recombination confirm that previously proposed transitions between 31 P and the interface defects take place. The influence of these electronic near-interface transitions on the 31 P donor spin coherence time T 2 as well as the donor spin-lattice relaxation time T 1 is then investigated by comparison of spin Hahn-echo decay measurements obtained from conventional bulk sensitive pulsed electron paramagnetic resonance and surface sensitive pEDMR, as well as surface sensitive electrically detected inversion recovery experiments. The measurements reveal that both T 2 and T 1 of 31 P donor electrons spins in proximity of energetically lower interface states at T ≤ 13 K are reduced by several orders of magnitude.

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Section: Discussionmentioning

confidence: 99%

Section: Experimental Datamentioning

confidence: 99%

T1andT2spin relaxation time limitations of phosphorous donor electrons near crystalline silicon to silicon dioxide interface defects

et al. 2010

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“…Some implications of this observable change have been discussed theoretically in previous studies on intermediate pairs for cases of no intrapair interactions 12,15 , cases of weak but non-negligible exchange interaction 16 (weak here means that the exchange interaction is much smaller than the spin-Zeeman splitting of the pair partners but not necessarily weaker than the difference of the pair partners Larmor frequencies), and for cases where disorder within the spin ensemble 17 is significant. These numerical studies have shown that an electrically detectable spin-Rabi oscillation can contain various harmonic components which can essentially form a "fingerprint" for the spin-Hamiltonian of the observed pairs.…”

Section: Introductionmentioning

confidence: 88%

Analytical description of spin-Rabi oscillation controlled electronic transitions rates between weakly coupled pairs of paramagnetic states withS=12

et al. 2013

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We report on an analytical description of spin-dependent electronic transition rates which are controlled by a radiation induced spin-Rabi oscillation of weakly spin-exchange and spin-dipolar coupled paramagnetic states (S = 1 2 ). The oscillation components (the Fourier content) of the net transition rates within spin-pair ensembles are derived for randomly distributed spin resonances with account of a possible correlation between the two distributions that correspond to the two individual pair partners. The results presented here show that when electrically or optically detected Rabi spectroscopy is conducted under an increasing driving field B1, the Rabi spectrum evolves from a single resonance peak at s = ΩR, where ΩR = γB1 is the Rabi frequency (γ is the gyromagnetic ratio), to three peaks at s = ΩR, s = 2ΩR, and at low s ΩR. The crossover between the two regimes takes place when ΩR exceeds the expectation value δ0 of the difference of the Zeeman energies within the pairs, which corresponds to the broadening of the magnetic resonance lines in the presence of disorder caused by hyperfine field or distributions of Landé g-factors. We capture this crossover by analytically calculating the shapes of all three peaks at arbitrary relation between ΩR and δ0. When the peaks are well-developed their widths are ∆s ∼ δ 2 0 /ΩR.

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“…The frequency is doubled to 2 W Rabi . [136,137] Rather than observing periodic Rabi flopping of a single frequency, as shown in Figure 8, this latter case of joint electron-hole precession at large B 1 fields will lead to spin precession at two frequencies, W Rabi and 2 W Rabi , within an ensemble of spins with a distribution of differences in hyperfine fields. Figure 10 c displays the integrated change in current flowing through an OLED operated in forward bias under electrical injection conditions as a function of time.…”

Section: From the Hyperfine Field To Coherent Spin Beatingmentioning

confidence: 99%

“…[131][132][133] Obviously, mere fitting of spectral lines is no proof of a particular model: exchange, hyperfine, spin-orbit, or spin-dipolar interactions could all contribute to the observed line shape, and may depend sensitively on the particular device configuration under investigation. [11,[134][135][136][137] The most obvious aspect to focus on is the hyperfine interaction, which describes the effect of the nuclear magnetic moment on the electron spin. The hyperfine interaction depends on the spin of the nucleus, which in turn is controlled by the particular isotope.…”

Section: From the Hyperfine Field To Coherent Spin Beatingmentioning

confidence: 99%

Coherent Spin Manipulation in Molecular Semiconductors: Getting a Handle on Organic Spintronics

Lupton¹,

McCamey²,

Boehme³

2010

ChemPhysChem

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Organic semiconductors offer expansive grounds to explore fundamental questions of spin physics in condensed matter systems. With the emergence of organic spintronics and renewed interest in magnetoresistive effects, which exploit the electron spin degree of freedom to encode and transmit information, there is much need to illuminate the underlying properties of spins in molecular electronic materials. For example, one may wish to identify over what length of time a spin maintains its orientation with respect to an external reference field. In addition, it is crucial to understand how adjacent spins arising, for example, in electrostatically coupled charge‐carrier pairs, interact with each other. A periodic perturbation of the field may cause the spins to precess or oscillate, akin to a spinning top experiencing a torque. The quantum mechanical characteristic of the spin is then defined as the coherence time, the time over which an oscillating spin, or spin pair, maintains a fixed phase with respect to the driving field. Electron spins in organic semiconductors provide a remarkable route to performing “hands‐on” quantum mechanics since permutation symmetries are controlled directly. Herein, we review some of the recent advances in organic spintronics and organic magnetoresistance, and offer an introductory description of the concept of pulsed, electrically detected magnetic resonance as a technique to manipulate and thus characterize the fundamental properties of electron spins. Spin‐dependent dissociation and recombination allow the observation of coherent spin motion in a working device, such as an organic light‐emitting diode. Remarkably, it is possible to distinguish between electron and hole spin resonances. The ubiquitous presence of hydrogen nuclei gives rise to strong hyperfine interactions, which appear to provide the basis for many of the magnetoresistive effects observed in these materials. Since hyperfine coupling causes quantum spin beating in electron–hole pairs, an extraordinarily sensitive probe for hyperfine fields in such pairs is given.

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Effect of exchange coupling on coherently controlled spin-dependent transition rates

Cited by 31 publications

References 12 publications

T1andT2spin relaxation time limitations of phosphorous donor electrons near crystalline silicon to silicon dioxide interface defects

T1andT2spin relaxation time limitations of phosphorous donor electrons near crystalline silicon to silicon dioxide interface defects

Analytical description of spin-Rabi oscillation controlled electronic transitions rates between weakly coupled pairs of paramagnetic states withS=12

Coherent Spin Manipulation in Molecular Semiconductors: Getting a Handle on Organic Spintronics

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