Coherent creation and destruction of orbital wavepackets in Si:P with electrical and optical read-out

Litvinenko, K. L.; Bowyer, E.; Greenland, P. T.; Stavrias, N.; Li, Juerong; Gwilliam, R.; Villis, B. J.; Matmon, Guy; Pang, M.; Redlich, Britta; Meer, A. F. G. van der; Pidgeon, C. R.; Aeppli, G.; Murdin, B. N.

doi:10.1038/ncomms7549

Cited by 38 publications

(43 citation statements)

References 25 publications

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“…Terahertz (THz) optical excitations (tuned to an energy-level spacing of approximately meV) can be used to manipulate and detect Rydberg states of donors by using a free-electron laser [16][17][18][19]. In the density range where donor pairs are dominant, the optical field has been used to detect and control the electron tunneling between donor pairs of phosphorus and antimony [20], while in three-donor clusters, the optical excitation (de-excitation) of a shallower "control" donor has the potential to switch on (off) the exchange interaction between the other two deeper donors, thus forming an optically controlled quantum gate [21,22].…”

Section: Introductionmentioning

confidence: 99%

Excited states of defect linear arrays in silicon: A first-principles study based on hydrogen cluster analogs

Greenland

Fisher

et al. 2018

Phys. Rev. B

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Excited states of a single donor in bulk silicon have previously been studied extensively based on effective mass theory. However, proper theoretical descriptions of the excited states of a donor cluster are still scarce. Here we study the excitations of lines of defects within a single-valley spherical band approximation, thus mapping the problem to a scaled hydrogen atom array. A series of detailed time-dependent Hartree-Fock, time-dependent hybrid density-functional theory and full configuration-interaction calculations have been performed to understand linear clusters of up to 10 donors. Our studies illustrate the generic features of their excited states, addressing the competition between formation of interdonor ionic states and intradonor atomic excited states. At short interdonor distances, excited states of donor molecules are dominant, at intermediate distances ionic states play an important role, and at long distances the intradonor excitations are predominant as expected. The calculations presented here emphasize the importance of correlations between donor electrons, and are thus complementary to other recent approaches that include effective mass anisotropy and multivalley effects. The exchange splittings between relevant excited states have also been estimated for a donor pair and for three-donor arrays; the splittings are much larger than those in the ground state in the range of donor separations between 10 and 20 nm. This establishes a solid theoretical basis for the use of excited-state exchange interactions for controllable quantum gate operations in silicon.

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Section: Introductionmentioning

confidence: 99%

Excited states of defect linear arrays in silicon: A first-principles study based on hydrogen cluster analogs

Greenland

Fisher

et al. 2018

Phys. Rev. B

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“…Electrical detection is sensitive. Typically, in these experiments we detect the ionization of about one donor in 10 4 , within a volume of ∼3 × 10 −9 m −3 implying a total of ∼10 7 excited electrons, and, as Fig. 6 shows, the limit is certainly an order of magnitude better than this.…”

Section: Discussionmentioning

confidence: 86%

“…However, phonon emission channels in Si lead to the rapid decay of excited states without a useful photon signal and this limits the number of excited donors which can be detected optically [3]. Very recently we have demonstrated the coherent creation and destruction, via Ramsey interference of picosecond pulse pairs, of orbital wave packets in Si:P with both optical and electrical read-out [4]. The electrical detection mechanism, termed photothermal ionization spectroscopy, is based on the much higher thermal ionization probability for an excited 2p ± state than the ground 1s state, implying that at finite temperature the sample conductivity directly reflects the strength of the 1s to 2p ± orbital transitions [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…Very recently we have demonstrated the coherent creation and destruction, via Ramsey interference of picosecond pulse pairs, of orbital wave packets in Si:P with both optical and electrical read-out [4]. The electrical detection mechanism, termed photothermal ionization spectroscopy, is based on the much higher thermal ionization probability for an excited 2p ± state than the ground 1s state, implying that at finite temperature the sample conductivity directly reflects the strength of the 1s to 2p ± orbital transitions [4][5][6][7]. Electrical detection of orbital excitation is by orders of magnitude more sensitive than the optical technique (see also Refs.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative analysis of electrically detected Ramsey fringes in P-doped Si

et al. 2015

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This work describes detection of the laser preparation and subsequent coherent manipulation of the quantum states of orbital levels of donors in doped Si, by measuring the voltage drop across an irradiated Si sample. This electrical signal, which arises from thermal ionization of excited orbital states, and which is detected on a millisecond time scale by a voltmeter, leads to much more sensitive detection than can be had using optical methods, but has not before been quantitatively described from first principles. We present here a unified theory which relates the voltage drop across the sample to the wave function of the excited donors, and compare its predictions to experiments in which pairs of picosecond pulses from the Dutch free-electron laser FELIX are used to resonantly and coherently excite P donors in Si. Although the voltage drop varies on a millisecond time scale we are able to measure Ramsey oscillation of the excitation on a picosecond time scale, thus confirming that the donor wave function, and not just its excited state population, is crucial in determining the electrical signal. We are also able to extract the recombination rate coefficient to the ground state of the donor as well as the photoionization cross section of the excited state and phonon induced thermal ionization rate from the excited state. These quantities, which were previously of limited interest, are here shown to be important in the description of electrical detection, which, in our unoptimized configuration, is sensitive enough to enable us to detect the excitation of ∼10 7 donors.

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“…In a Ramsey interference experiment the coherence produced by the pump pulse can be either enhanced or destroyed by a second pulse depending on their phase difference, and the envelope of the fringes reveals T * 2 [8]. In each of these cases frequency-domain experiments can be used to obtain the same information, but time-domain versions can be preferable when there are multiple processes responsible for the decays as well as static, inhomogeneous broadening effects that must be separated from dynamics.…”

Section: Introductionmentioning

confidence: 99%

Weak probe readout of coherent impurity orbital superpositions in silicon

et al. 2016

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Pump-probe spectroscopy is the most common time-resolved technique for investigation of electronic dynamics, and the results provide the incoherent population decay time T 1 . Here we use a modified pump-probe experiment to investigate coherent dynamics, and we demonstrate this with a measurement of the inhomogeneous dephasing time T * 2 for phosphorus impurities in silicon. The pulse sequence produces the same information as previous coherent all-optical (photon-echo-based) techniques but is simpler. The probe signal strength is first order in the pulse area but its effect on the target state is only second order, meaning that it does not demolish the quantum information. We propose simple extensions to the technique to measure the homogeneous dephasing time T 2 , or to perform tomography of the target qubit.

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Coherent creation and destruction of orbital wavepackets in Si:P with electrical and optical read-out

Cited by 38 publications

References 25 publications

Excited states of defect linear arrays in silicon: A first-principles study based on hydrogen cluster analogs

Excited states of defect linear arrays in silicon: A first-principles study based on hydrogen cluster analogs

Quantitative analysis of electrically detected Ramsey fringes in P-doped Si

Weak probe readout of coherent impurity orbital superpositions in silicon

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