Electrical Detection of Coherent Nuclear Spin Oscillations in Phosphorus-Doped Silicon using Pulsed ENDOR

Hoehne, Felix; Dreher, Lukas; Huebl, Hans; Stutzmann, M.; Brandt, Martin S.

doi:10.1103/physrevlett.106.187601

Cited by 38 publications

(46 citation statements)

References 25 publications

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“…However, whilst the nuclear spin lifetime (T n 1 ) imposes a limit on the storage of classical information, it is the nuclear spin phase coherence time (T n 2 ) which sets a limit on the storage of quantum information, usually shorter than the spin lifetime. Here, we utilize a spin echo technique to show that electrical readout of donor nuclear spins is compatible with phase coherence times T n 2 exceeding 2 ms, nearly two orders of magnitude longer than that previously seen 12 . We also determine that the artificially shortened donor electron lifetime T e 1 limits T n 2 via hyperfine coupling to the nuclei 7 , and discuss ways to overcome this limitation.…”

Section: Introductionmentioning

confidence: 90%

“…For example, coupling the donor electron to the island of a nearby single electron transistor can allow single spin readout 14 , although readout of coherent states of the electron using this technique has not yet been reported in the literature. Hoehne et al 12 have recently shown that electrical readout of coherent nuclear spin motion could be detected using spin dependent recombination, although phase coherence times are limited to T n 2 ∼ 50µs in those measurements. Here, we utilize spin-dependent trapping of photoexcited electrons into the D − state of the 31 P donor 19,20 [ Fig.…”

Section: Introductionmentioning

confidence: 99%

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Electrically detected spin echoes of donor nuclei in silicon

et al. 2012

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The ability to probe the spin properties of solid state systems electrically underlies a wide variety of emerging technology. Here, we demonstrate electrical readout of the nuclear spin states of phosphorus donors in silicon in the coherent regime with modified Hahn echo sequences. We find that, whilst the nuclear spins have electrically detected phase coherence times exceeding 2 ms, they are nonetheless limited by the artificially shortened lifetime of the probing donor electron.

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Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Electrically detected spin echoes of donor nuclei in silicon

et al. 2012

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“…The system then evolves freely for a mixing time T, and a stimulated echo is generated by another π/2 pulse. The final π/2 readout pulse is required for electrical detection when the spin-dependent current is governed by spin permutation symmetry rather than spin polarization [4,56,57]. Fig.…”

Section: Appendix D: Eseem Experimentsmentioning

confidence: 99%

Morphology effects on spin-dependent transport and recombination in polyfluorene thin films

et al. 2016

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We have studied the role of spin-dependent processes on conductivity in polyfluorene (PFO) thin films by conducting continuous wave (c.w.) electrically detected magnetic resonance (EDMR) spectroscopy at temperatures between 10 K and 293 K using microwave frequencies between about 100 MHz and 20 GHz as well as pulsed EDMR at X-band (10 GHz). Variable frequency EDMR allows us to establish the role of spin-orbit coupling in spin-dependent processes whereas pulsed EDMR allows for the observation of coherent spin motion effects. We used PFO for this study in order to allow for the investigation of the effects of microscopic morphological ordering since this material can adopt two distinct intrachain morphologies: an amorphous (glassy) phase, in which monomer units are twisted with respect to each other, and an ordered (β) phase, where all monomers lie within one plane. In thin films of organic light-emitting diodes (OLEDs) the appearance of a particular phase can be controlled by deposition parameters and solvent vapor annealing, and is verified by electroluminescence spectroscopy. Under bipolar charge carrier 2 injection conditions we conducted multi-frequency c.w. EDMR, electrically detected Rabi spinbeat experiments, Hahn-echo and inversion-recovery measurements. Coherent echo spectroscopy reveals electrically detected electron spin-echo envelope modulation (ESEEM) due to the coupling of the carrier spins to nearby nuclei spins. Our results demonstrate that while conformational disorder can influence the observed EDMR signals, including the sign of the current changes on resonance as well as the magnitudes of local hyperfine fields and charge carrier spin-orbit interactions, it does not qualitatively affect the nature of spin-dependent transitions in this material. In both morphologies, we observe the presence of at least two different spin-dependent recombination processes. At 293 K and 10 K, polaron-pair recombination through weakly spin-spin coupled intermediate charge carrier pair states is dominant, while at low temperatures, additional signatures of spin-dependent charge transport through the interaction of polarons with triplet excitons are seen in the half-field resonance of a triplet spin-1 species. This additional contribution arises since triplet lifetimes are increased at lower temperatures. We tentatively conclude that spectral broadening induced by hyperfine coupling is slightly weaker in the more ordered β-phase than in the glassy-phase, since protons are more evenly spaced, whereas broadening effects due to spin-orbit coupling, which impacts the distribution of g-factors, appears to be somewhat more significant in the β-phase. PACS

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“…This scheme allows to extend the experimental methods of pEDMR to more advanced pulse sequences 16,17 and opens its application to other materials and spin-dependent processes to be studied with this technique.…”

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confidence: 99%

Lock-in detection for pulsed electrically detected magnetic resonance

Hoehne

Dreher

Behrends

et al. 2012

Review of Scientific Instruments

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We show that in pulsed electrically detected magnetic resonance (pEDMR) signal modulation in combination with a lock-in detection scheme can reduce the low-frequency noise level by one order of magnitude and in addition removes the microwave-induced non-resonant background. This is exemplarily demonstrated for spin-echo measurements in phosphorus-doped Silicon. The modulation of the signal is achieved by cycling the phase of the projection pulse used in pEDMR for the read-out of the spin state. Electron paramagnetic resonance (EPR) has proven to be a powerful tool in the characterization of defects in semiconductors 1 . However, EPR is rather insensitive and typically limited to samples with more than 10 10 spins 2 . Due to its higher sensitivity, electrically detected magnetic resonance (EDMR) is now widely used to study defects, in particular in indirect, disordered or organic semiconductors 3-8 . Over the last years, pulsed EDMR (pEDMR) has gained considerable interest, since it combines the large toolbox of pulsed EPR methods 9with the enhanced sensitivity of EDMR e.g. to identify spin-dependent transport and recombination processes and study hyperfine interactions 10-18 . However, in many cases pEDMR suffers from strong low-frequency noise and large non-resonant background signals induced by the strong microwave pulses used to manipulate the spin system 11 . Here, we demonstrate that for pEDMR, a lock-in detection scheme is able to subtract the non-resonant background and effectively reduce low-frequency noise by more than one order of magnitude following similar ideas that have been applied in conventional pulsed EPR spectroscopy 19 .In the pulsed EDMR discussed here, the symmetry of a spin pair is changed by resonant microwave pulses resulting in a change of the recombination rate of excess carriers, which is reflected in a current transient after the microwave pulses. The pEDMR signal is obtained by box-car integrating the current transient after the pulse sequence over a time interval ∆t, resulting in a charge ∆Q proportional to the recombination rate at the end of the pulse sequence 10 , as schematically shown in Fig. 1 (a). However, the strong microwave pulses also cause spin-independent non-resonant changes of the current due to e.g. rectification in the semiconductor sample resulting in additional noise and background signals which are typically much larger than the spin-dependent signals. These effects can be mitigated by using a lock-in detection scheme for pEDMR measurements, as will be described in the following.Lock-in detection employs modulation of a signal at a certain frequency and its phasesensitive detection in combination with bandpass filtering 20 . We will discuss how such a scheme can be implemented in pEDMR exemplarily for the measurement of electrically detected spin echoes. We use a π/2-τ 1 -π-τ 2 -π/2 spin-echo pulse-sequence, where π/2 and π denote microwave pulses with corresponding flipping angles and τ 1 and τ 2 denote the duration of periods of free evolution [ Fig. 1 (a)] 21...

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Electrical Detection of Coherent Nuclear Spin Oscillations in Phosphorus-Doped Silicon using Pulsed ENDOR

Cited by 38 publications

References 25 publications

Electrically detected spin echoes of donor nuclei in silicon

Electrically detected spin echoes of donor nuclei in silicon

Morphology effects on spin-dependent transport and recombination in polyfluorene thin films

Lock-in detection for pulsed electrically detected magnetic resonance

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