Acoustic manipulation of electron-hole pairs in GaAs at room temperature

We demonstrate the optically detected long-range (>100 µm) ambipolar transport of photogenerated electrons and holes at room temperature by surface acoustic waves (SAWs) in (In,Ga)As-based quantum well structures coupled to an optical microcavity. We also show the control of the propagation direction of the carriers by a switch composed of orthogonal SAWbeams, which can be used as a basic control gate for information processing based on ambipolar transport

Franck-Condon Effect in Central Spin System

We study the quantum transitions of a central spin surrounded by a collective-spin environment. It is found that the influence of the environmental spins on the absorption spectrum of the central spin can be explained with the analog of the Franck-Condon (FC) effect in conventional electron-phonon interaction system. Here, the collective spins of the environment behave as the vibrational mode, which makes the electron to be transitioned mainly with the so-called "vertical transitions" in the conventional FC effect. The "vertical transition" for the central spin in the spin environment manifests as, the certain collective spin states of the environment is favored, which corresponds to the minimal change in the average of the total spin angular momentum.Comment: 8 pages, 8 figure

Enhanced spin coherence via mesoscopic confinement during acoustically induced transport

Long coherence lifetimes of electron spins transported using moving potential dots are shown to result from the mesoscopic confinement of the spin vector. The confinement condition to control electron spin dephasing is governed by the relation between the characteristic spin–orbit length of the electron spins and the dimensions of the dot potential, which governs the electron spin coherence lifetime. The spin–orbit length is a sample-dependent parameter determined by the Dresselhaus contribution to the spin–orbit coupling and can be predictably controlled by varying the sample geometry. We further show that the coherence lifetime of the electron spins is independent of the local carrier densities within each potential dot, which suggests the possibility of coherent, long-range transport of single electron spins

Coherent Spin Transport By Acoustic Fields In Gaas Quantum Wells

We review processes for long-range spin transport and manipulation in GaAs quantum wells using mobile potentials created by the piezoelectric field of a surface acoustic wave. By reducing spin dephasing mechanisms associated with the spin orbit-coupling, these potentials can coherently transport spins over distances on the order of 100 μm. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.31243074312Prinz, G.A., (1995) Phys. Today, 48, p. 58Smet, J.H., (2002) Nature, 415, p. 281Zrenner, A., (2002) Nature, 418, p. 612Datta, S., Das, B., (1990) Appl. Phys. Lett, 56, p. 665Stotz, J.A.H., Hey, R., Santos, P.V., Ploog, K.H., (2005) Nature Mater, 4, p. 584Santos, P.V., Stotz, J.A.H., Hey, R., (2005) Realizing controllable quantum states: Proc. of the Int. Symp. on Mesoscopic Superconductivity and Spintronics - In the light of quantum computation, p. 357. , edited by H. Takayanagi and J. Nitta World Scientific, SingaporeSogawa, T., (2001) Phys. Rev. Lett, 87, p. 276601Rocke, C., (1997) Phys. Rev. Lett, 78, p. 4099Barnes, C.H.W., Shilton, J.M., Robinson, A.M., (2000) Phys. Rev. B, 62, p. 8410Alsina, F., Stotz, J.A.H., Hey, R., Santos, P.V., (2004) Solid State Commun, 129, p. 453Ohno, Y., (1999) Phys. Rev. Lett, 83, p. 4196D'yakonov, M.I., Perel', V.I., (1972) Sov. Phys. Solid State, 13, p. 3023Dyakonov, M.I., Kachorovskii, V.Y.Y., (1986) Sov. Phys. Semicond, 20, p. 110Stotz, J.A.H., Hey, R., Santos, P.V., (2005) Mater. Sci. Eng. B, 126, p. 164Kikkawa, J.M., Awschalom, D.D., (1999) Nature, 397, p. 139Stotz, J.A.H., Santos, P.V., Hey, R., Ploog, K.H., unpublishedGovorov, A.O., (2001) Phys. Rev. Lett, 87, p. 226803Adachi, T., Ohno, Y., Matsukura, F., Ohno, H., (2001) Physica E, 10, p. 36Karimov, O.Z., (2003) Phys. Rev. Lett, 91, p. 246601Döhrmann, S., (2004) Phys. Rev. Lett, 93, p. 147405Hall, K.C., (2004) Phys. Rev. B, 68, p. 11531

Acoustically-driven Single Photon Sources On (311)a Gaas

We employ surface acoustic waves to control the transfer of photo-generated carriers between interconnected quantum wells and wires grown on pre-patterned (311)A GaAs substrates. The wires are embedded at photo-lithographically defined positions within (Al,Ga)As/GaAs quantum well. Optical studies on these structures have shown sharp PL lines and antibunched photons with tunable emission energy, revealing the presence of several recombination centers within the wire. The spatial separation of these recombination centers emitting single photons is determined from time-resolved measurements. © 2011 American Institute of Physics.139910351036Int. Union Pure Appl. Phys. (IUPAP C8 Comm.),Korean Ministry of Education, Science and Technology,Seoul Metropolitan Government,Office of Naval Research Global,Korea Tourism OrganizationRocke, C., (1997) Phys. Rev. Lett., 78, p. 4099Notzel, (1996) Appl. Phys. Lett., 68, p. 1132Hey, R., (2004) Physica E, 21, p. 737Couto, O.D.D., (2009) Nat. Photonics, 3, p. 645Intonti, (2001) Phys. Rev. B, 63, p. 07531

Photon Anti-bunching In Acoustically Pumped Quantum Dots

Although extensive research on nanostructures has led to the discovery of a number of efficient ways to confine carriers in reduced dimensions, little has been done to make use of the unique properties of various nanostructured systems through coupling by means of the controllable transfer of carriers between them. Here, we demonstrate a novel approach for the controllable transfer of electrons and holes between a semiconductor quantum well and an embedded quantum dot using the moving piezoelectric potential modulation induced by an acoustic phonon. We show that this moving potential not only transfers carriers between the quantum well and an array of quantum dots, but can also control their capture and recombination in discrete quantum dot states within the array. This feature is used to demonstrate a high-frequency, single-photon source with tunable emission energy by acoustically transferring carriers to a selected quantum dot. © 2009 Macmillan Publishers Limited.311645648Shilton, J.M., High-frequency single-electron transport in a quasi-onedimensional GaAs channel induced by surface acoustic waves (1996) J. Phys. Condens. Matter, 8, pp. L531-L539Rocke, C., Acoustically driven storage of light in a quantum well (1997) Phys. Rev. Lett., 78, pp. 4099-4102Sogawa, T., Transport and lifetime enhancement of photoexcited spins in GaAs by surface acoustic waves (2001) Phys. Rev. Lett., 87, p. 276601Rudolph, J., Hey, R., Santos, P.V., Long-range exciton transport by dynamic strain fields in a GaAs quantum well (2007) Phys. Rev. Lett., 99, p. 047602Imamoglu, A., Yamamoto, Y., Nonclassical light generation by Coulomb blockade of resonant tunneling (1992) Phys. Rev. B, 46, p. 015982Wiele, C., Photon trains and lasing: The periodically pumped quantum dot (1998) Phys. Rev. A, 58, pp. R2680-R2683Foden, C.L., High-frequency acousto-electric single-photon source (2000) Phys. Rev. A, 62, p. 011803Stotz, J.A.H., Hey, R., Santos, P.V., Ploog, K.H., Coherent spin transport via dynamic quantum dots (2005) Nature Mater., 4, pp. 585-588Couto Jr, O.D.D., Iikawa, F., Rudolph, J., Hey, R., Santos, P.V., Anisotropic spin transport in(110) GaAs quantum wells (2007) Phys. Rev. Lett., 98, p. 036603Lounis, B., Orrit, M., Single-photon sources (2005) Rep. Prog. Phys., 68, pp. 1129-1179Hosey, T., Lateral n-p junction for acoustoelectric nanocircuits (2004) Appl. Phys. Lett., 85, pp. 491-493Bodefeld, C., Experimental investigation towards a periodically pumped single-photon source (2006) Phys. Rev. B, 74, p. 035407Notzel, R., Selectivity of growth on patterned GaAs(311)A substrates (1996) Appl. Phys. Lett., 68, pp. 1132-1134Hey, R., Conductance anisotropy of high-mobility two-dimensional hole gas at GaAs/(Al,Ga)As(1 1 3)A single heterojunctions (2004) Physica e, 21, pp. 737-741Intonti, F., Near-field optical spectroscopy of localized and delocalized excitons in a single GaAs quantum wire (2001) Phys. Rev. B, 63, p. 075313Sogawa, T., Dynamic band-structure modulation of quantum wells by surface acoustic waves (2001) Phys. Rev. B, 63, p. 121307De Lima Jr, M.M., Santos, P.V., Modulation of photonic structures by surface acoustic waves (2005) Rep. Prog. Phys., 68, pp. 1639-1701Hanbury-Brown, R., Twiss, R.Q., (1956) Nature, 177, pp. 27-29Bennett, A.J., Electrical control of the uncertainty in the time of single photon emission events (2005) Phys. Rev. B, 72, p. 03331

Evidence For Photon Anti-bunching In Acoustically Pumped Dots

We demonstrate the controlled transfer of photoexcited carriers by a surface acoustic wave (SAW) between coupled quantum wells, wires, and dots grown on a semiconductor surface. The quantum wires and dots used in the experiments are embedded at photolithographically defined positions within an (Al,Ga)As/GaAs (311)A-oriented quantum well grown by molecular beam epitaxy. We give experimental evidence for the anti-bunching of photons emitted in a quantum dot pumped by electrons and holes transported from the quantum well by a surface acoustic wave. © 2009 Elsevier B.V. All rights reserved.421024972500Sogawa, T., Santos, P.V., Zhang, S.K., Eshlaghi, S., Wieck, A.D., Ploog, K.H., (2001) Phys. Rev. Lett., 87, pp. 276601-1Stotz, J.A.H., Hey, R., Santos, P.V., Ploog, K.H., (2005) Nat. Mater., 4, p. 585Couto Jr., O.D.D., Iikawa, F., Rudolph, J., Hey, R., Santos, P.V., (2007) Phys. Rev. Lett., 98, p. 036603Wiele, C., Haake, F., Rocke, C., Wixforth, A., (1998) Phys. Rev. A, 58, p. 2680Foden, C.L., Talyanskii, V.I., Milburn, G.J., Leadbeater, M.L., Pepper, M., (2000) Phys. Rev. A, 62, pp. 011803RHosey, T., Talyanskii, V., Vijendran, S., Jones, G.A.C., Ward, M.B., Unitt, D.C., Norman, C.E., Shields, A.J., (2004) Appl. Phys. Lett., 85, p. 491Bdefeld, C., Ebbecke, J., Toivonen, J., Sopanen, M., Lipsanen, H., Wixforth, A., (2006) Phys. Rev. B, 74 (3), p. 035407Ntzel, R., Menniger, J., Ramsteiner, M., Ruiz, A., Schnherr, H.-P., Ploog, K.H., (1996) Appl. Phys. Lett., 68, p. 1132De Lima Jr., M.M., Santos, P.V., (2005) Rep. Prog. Phys., 68, p. 1639Couto Jr., O.D.D., (2009) Nat. Photonics, 3, p. 64