Spin-dependent recombination in GaAsN solid solutions

Kalevich, V. K.; Ivchenko, E. L.; Afanasiev, M. M.; Shiryaev, A. Yu.; Egorov, A. Yu.; Ustinov, V. M.; Pal, Bipul; Masumoto, Yasuaki

doi:10.1134/1.2142877

Cited by 49 publications

(120 citation statements)

References 7 publications

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“…After the subsequent recombination between one of two localized electrons and an unpolarized free hole (due to much faster spin relaxation), a half number of the Ga i 2+ are left with a localized electron with its spin orientation parallel to that of the conduction electrons. Such a continuous SDR process [16][17][18][19][20][21] will dynamically polarize the spin of the first localized electrons at the Ga i 2+ towards that of conduction electrons.…”

Section: +mentioning

confidence: 99%

“…on the number of photo-generated free carriers). Representative results obtained at RT and B=0 are shown in Fig.3, and were analyzed by the following coupled nonlinear rate equations 19,21 : Here G ± is the photo-generation rate of free carriers and n ± (N ± ) the density of conduction electrons (the density of the defects occupied by a single electron), where the "±" signs refer to the electron spin orientations S z =±1/2. N ↑↓ corresponds to the concentration of the defects having two spin-paired electrons, and N c the total defect concentration.…”

Section: +mentioning

confidence: 99%

“…In the analysis we use τ d =10 ns, τ sc =1.5 ns and τ s =150 ps. 19,21 Here we assume that τ d is governed by the radiative time of the BB PL transition. The analysis is not sensitive to τ d as long as it is much longer than the electron capture & recombination time via the spin-filtering defects, i.e.…”

Section: +mentioning

confidence: 99%

“…Spin polarization of the electrons at Ga i 2+ was provided by optical orientation 15 using circularly polarized light (σ ± ) via spin-dependent recombination (SDR) [16][17][18][19][20][21] , as described in the "Methods" section . The spin-filtering effect induced by the spin-polarized defects drives the spins of the conduction and localized electrons at Ga i 2+ towards complete alignment when no further electron capture and recombination can occur via the defects as shown in Fig.1b.…”

Section: +mentioning

confidence: 99%

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Room-temperature defect-engineered spin filter based on a non-magnetic semiconductor

et al. 2009

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confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Room-temperature defect-engineered spin filter based on a non-magnetic semiconductor

et al. 2009

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“…Our approach exploits the recently discovered defect-engineered spin-filtering effect 25 , which has been demonstrated to be capable of generating strong spin polarization of conduction-band electrons in a semiconductor at RT. Strong conduction-band electron spin polarization of 440% can be obtained at RT in Ga(In)NAs by spin-filtering through Ga i interstitial defects [25][26][27][28][29] . By taking advantage of the spin-filtering effect and going beyond merely generating conduction-band electron spin polarization that was the focal point of the previous studies [25][26][27][28][29] , we shall show in this work that strong and efficient nuclear spin polarization of the core Ga atom of the Ga i defects can be achieved at RT by optical orientation.…”

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Efficient room-temperature nuclear spin hyperpolarization of a defect atom in a semiconductor

et al. 2013

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Nuclear spin hyperpolarization is essential to future solid-state quantum computation using nuclear spin qubits and in highly sensitive magnetic resonance imaging. Though efficient dynamic nuclear polarization in semiconductors has been demonstrated at low temperatures for decades, its realization at room temperature is largely lacking. Here we demonstrate that a combined effect of efficient spin-dependent recombination and hyperfine coupling can facilitate strong dynamic nuclear polarization of a defect atom in a semiconductor at room temperature. We provide direct evidence that a sizeable nuclear field (B150 Gauss) and nuclear spin polarization (B15%) sensed by conduction electrons in GaNAs originates from dynamic nuclear polarization of a Ga interstitial defect. We further show that the dynamic nuclear polarization process is remarkably fast and is completed in o5 ms at room temperature. The proposed new concept could pave a way to overcome a major obstacle in achieving strong dynamic nuclear polarization at room temperature, desirable for practical device applications.

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Room‐Temperature Electron Spin Amplifier Based on Ga(In)NAs Alloys

et al. 2012

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Efficient generation, maintaining, manipulation and detection of electron spin polarization and coherence at room-temperature (RT) in semiconductors is a prerequisite for the success of future semiconductor spintronics and quantum information technologies. [1][2][3][4][5] Potential spintronic devices are expected to be based on fundamental building blocks such as spin filters (or spin injectors or spin aligners), spin amplifiers and spin detectors. During the past decade spin filters and spin detectors have been a main focal point of intense research efforts in the field of semiconductor spintronics that have led to many innovative approaches and encouraging developments. [1][2][3][4][5] In sharp contrast, experimental developments in spin amplifiers have so far been extremely limited. This is despite of the facts that many theoretical proposals for a wide variety of model spin amplifiers have been suggested during the past decade, ranging from spin amplifiers using spin injection pillar [6,7] or a dual-drain nonlocal lateral spin valve [8] or non-magnetic semiconductors, [9] unipolar spin transistors, [10] Submitted to 2 magnetic dipolar transistors, [11,12] spin gain transistors, [13] and optically controlled spin transistors. [14] As most of the proposed models require the involvement of a spin-functional diluted magnetic semiconductors (DMS), a lack of true DMS that can provide spin-polarized carriers at RT has so far prevented experimental realization of these proposed spin amplifiers.To our knowledge, the highest temperature at which a spin amplifier has so far been experimentally demonstrated to function is 150 K using a dual-drain nonlocal lateral spin valve based on an ferromagnetic metal-semiconductor hybrid structure. [8] Here we propose and demonstrate a new concept of a defect-enabled spin amplifier based on a non-magnetic semiconductor (Figure 1a). We shall show that a large spin gain (up to 2700 %) can be obtained at RT by employing Ga(In)NAs. This spin amplification functionality is facilitated by the spin-dependent recombination processes via defects, [15][16][17] which was also recently explored for spin filtering. [15,18] Spin amplification in the proposed spin amplifier is self-triggered by incoming conduction electrons with a finite spin polarization regardless of how weak and which direction the spin polarization is. Therefore, the sign of the spin polarization of the outgoing electrons from such a spin amplifier exactly follows that of the incoming electrons. Such spin amplification is generally efficient because even very weak spin polarization of incoming conduction electrons can dynamically polarize the spins of the defect electrons to a much greater degree, thanks to a much longer spin lifetime of the defect electrons commonly known in semiconductors. The spin-polarized defects can then in turn selectively capture and deplete conduction electrons with an opposite spin orientation (i.e. minority spin) governed by the Pauli exclusion principle, leading to greatly enhanced spin polarizat...

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Spin-dependent recombination in GaAsN solid solutions

Cited by 49 publications

References 7 publications

Room-temperature defect-engineered spin filter based on a non-magnetic semiconductor

Room-temperature defect-engineered spin filter based on a non-magnetic semiconductor

Efficient room-temperature nuclear spin hyperpolarization of a defect atom in a semiconductor

Room‐Temperature Electron Spin Amplifier Based on Ga(In)NAs Alloys

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