Submillisecond electron spin relaxation in InP quantum dots

Ikezawa, Michio; Pal, Bipul; Masumoto, Yasuaki; Ignatiev, I. V.; Verbin, S. Yu.; Gerlovin, I. Ya.

doi:10.1103/physrevb.72.153302

Cited by 58 publications

(82 citation statements)

References 15 publications

(16 reference statements)

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“…Semi-transparent indiumtin-oxide electrode is deposited on top of the sample to control the charge state of the QDs by means of an applied electric bias. 5,6,17 For the present study on the singly negatively charged QDs we apply an electric bias of U b = −0.1 V. This is because it was found from a previous study of trionic quantum beats 17 on the same sample that at U b ≈ −0.1 V the QDs contain one resident electron per dot, on an average.…”

Section: Methodsmentioning

confidence: 99%

“…3,4 Charge-tunable InP QDs with one resident electron per dot, on an average, have recently attracted considerable research interest due to the observation of submillisecond spin lifetime of resident electrons in these QDs. 5,6 This observation makes it a promising candidate for quantum memory element in the emerging fields of quantum information technology and spintronics. 7 Application of QDs as the building blocks of quantum computers has been proposed.…”

Section: Introductionmentioning

confidence: 99%

“…II. Our time-domain measurements of ρ c by using a PL pump-probe technique 5,6,15,16 in the microsecond time-regime reveal electron spin relaxation via the NSPE at the vanishing external magnetic field. From the value of the electron spin decay time τ d for B ext = 0, we estimate that T N ∼ 1 µs at T ≈ 5 K, comparable to the theoretical estimate available for GaAs QDs.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper we describe our experimental study of nuclear spin effects on the long-lived spin polarization of resident electrons, observed recently 5,6 in the singly negatively charged InP QDs. Electron spin dynamics and the influence of nuclear spins on it, are probed by the timeresolved as well as time-integrated measurements of the degree of PL circular polarization ρ c , defined quantitatively in Sec.…”

Section: Introductionmentioning

confidence: 99%

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Nuclear-spin effects in singly negatively charged InP quantum dots

et al. 2007

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Experimental investigation of nuclear spin effects on the electron spin polarization in singly negatively charged InP quantum dots is reported. Pump-probe photoluminescence measurements of electron spin relaxation in the microsecond timescale are used to estimate the time-period TN of the Larmor precession of nuclear spins in the hyperfine field of electrons. We find TN to be ∼ 1 µs at T ≈ 5 K, under the vanishing external magnetic field. From the time-integrated measurements of electron spin polarization as a function of a longitudinally applied magnetic field at T ≈ 5 K, we find that the Overhauser field appearing due to the dynamic nuclear polarization increases linearly with the excitation power, though its magnitude remains smaller than 10 mT up to the highest excitation power (50 mW) used in these experiments. The effective magnetic field of the frozen fluctuations of nuclear spins is found to be 15 mT, independent of the excitation power.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nuclear-spin effects in singly negatively charged InP quantum dots

et al. 2007

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“…Until now, to measure a long spin relaxation time, authors have mainly adopted solutions based on the detection of the polarized photoluminescence excited by a probe beam, which has been delayed with respect to a previous pump beam. [37][38][39] By changing the time delay between the pump and probe beams, a signature of the spin polarization in the time domain is obtained. In this configuration, the intensity of excitation is modulated by an acousto-optic modulator in order to make a difference between the pump and probe pulses through the variation of the pulse temporal width, rather than the pulse power intensity (which is the common way in the two-beam pump-probe configuration).…”

Section: B Experiments In Frequency Domain: Dark-bright Time-scanninmentioning

confidence: 99%

Hole-spin initialization and relaxation times in InAs/GaAs quantum dots

et al. 2011

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We study, at low temperature and zero magnetic field, the hole-spin dynamics in InAs/GaAs quantum dots. We measure the hole-spin relaxation time at a time scale longer than the dephasing time (about ten nanoseconds), imposed by the hole-nuclear hyperfine coupling. We use a pump-probe configuration and compare two experimental techniques based on differential absorption. The first one works in the time domain, and the second one is a new experimental method, the dark-bright time-scanning spectroscopy (DTS), working in the frequency domain. The measured hole-spin relaxation times, using these two techniques, are very similar, in the order of T h N ≈1 μs. It is mainly imposed by the inhomogeneous hole hyperfine coupling in the hole localization volume. The DTS technique allows us also to measure the hole-spin initialization time τ i . The hole spin is initialized by a periodic train of circularly polarized pulses at 76 MHz; we have observed that τ i decreases as the power density increases, and we have measured a minimum value of τ i ≈100 ns in good agreement with a simple model [seeB. Eble, P. Desfonds, F. Fras, F. Bernardot, C. Testelin, M. Chamarro, A. Miard, and A. Lemaître, Phys. Rev. B 81, 045322 (2010)].

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Monolithic and Hybrid Spintronics

Bandyopadhyay

2010

Nanotechnology

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“Spintronics” is the science and technology of using the spin degree of freedom of a charge carrier, either singly or in conjunction with the charge, to store, process and/or communicate information. Both, classical and quantum mechanical information can be encoded by spin. In this chapter, “hybrid” and “monolithic” spintronics are discussed; the distinction between the two is that, in the former case, spin is not used directly to store or process information; rather, that role is still delegated to charge. But spin influences how charge stores or manipulates information. The role of spin is secondary and may, at best, augment the role of charge. Examples of hybrid spintronic devices are spin field effect transistors (SPINFETs) and spin bipolar junction transistors (SBJTs). It is also noted that hybrid devices are not likely to yield major advances in device engineering in the short term. On the other hand, monolithic spintronics, which deals with devices in which spin single‐handedly stores and processes information, is much better poised to make major advances. An example of this is “single spin logic” (SSL), where a single electron acts as a binary element (two‐state switch), its two orthogonal spin polarizations being used to encode binary bits 0 and 1. Switching between bits is accomplished simply by flipping the spin of the electron, without physically moving charges in space and causing a current flow. In this way energy is saved, leading to a much‐reduced power dissipation. The switching time is also not limited by the speed of charge carriers as there is no charge motion. The maximum energy dissipated in SSL gate operation is the Landauer–Shannon limit of kT ln( p ) per operation (where 1/ p is the error probability). The chapter concludes with a brief discussion of spin‐based quantum computing, where the spin of an electron in a quantum dot is used to implement a qubit. Of note, this last section is necessarily brief and will most likely be outdated by the time this book is printed, as rapid strides are being made in that area.

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Submillisecond electron spin relaxation in InP quantum dots

Cited by 58 publications

References 15 publications

Nuclear-spin effects in singly negatively charged InP quantum dots

Nuclear-spin effects in singly negatively charged InP quantum dots

Hole-spin initialization and relaxation times in InAs/GaAs quantum dots

Monolithic and Hybrid Spintronics

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