SFB 689: Spin Phenomena in Reduced Dimensions
Final Report Abstract
Within the Collaborative Research Center (SFB 689) we explored „Spin-phenomena in reduced dimensions” involving the characterization, control and manipulation of the spin degree of freedom in low dimensional systems like carbon nanotubes (cylindrical carbon nanostructures), graphene (a single atomic layer of carbon), semiconductor films and two-dimensional electron systems, or individual molecules and arrangements of individual atoms on surfaces. The spin is a quantum mechanical property of elementary particles like electrons and behaves like an angular momentum. In case of an electron the spin has angular momentum ±½ħ with the reduced Planck constant ħ. The magnetic moment associated with the spin thus has only two orientations, parallel and anti-parallel to an applied magnetic field. Within SFB 689, or more generally in the field of spintronics, one tries utilizing the electron’s spin in addition to its elementary charge -e to realize new functionalities which could be used in electronics or in quantum computation. An important quantity which characterizes the spin is its relaxation time, i.e. the time it takes a spin population with specific orientation to decay. A characteristic device which uses the spin of the electrons in addition to its charge is the spin-transistor which was proposed nearly three decades ago but still awaits realization. Even molecules could show transistor functionality if spin is involved. These are only a few examples of the issues addressed in the consortium. In the project period many important discoveries were made and concepts developed which contribute to the cutting edge of research in the field. One example is a new theory for spin relaxation in graphene which is based on the concept of resonant scattering and is in excellent agreement with experiments. We also found that carbon nanotubes in combination with superconductors can be used to generate quantum mechanically entangled electrons. Entanglement effects might be used in communication and computation. Another vivid result is resolution of the spin orientation of neighboring atoms in a NiO single crystal. By using atomic force microscopy we could directly visualize the antiferromagnetic order in NiO crystals. The “holy grail” of spintronics is efficient all electrical spin injection and detection which has been identified as one of the central goals of SFB 689. In these experiments one injects spins from a ferromag- netic injector into a nonmagnetic material like a two-dimensional electron gas in graphene or in a semiconductor heterostructures. Using sort of inverse process, the accumulated spins can be probed elec- trically. The resulting spin dependent resistance changes were typically below 1%. By using ferromagnetic semiconductors (grown in house), spin-valve geometry and epitaxial interfaces we were able to reach spin dependent resistance changes of up to 80%. Even a spin solar cell could be realized in which light generates a spin current. One effect which has been thoroughly studied, both theoretically and experimentally, is the spin Hall effect. For the first time the so called acSHE could be observed and parasitic voltages mimicking a dc inverse spin Hall effect could be avoided by using a proper measurement geometry. A valuable asset of the SFB was the close cooperation between theory and experiment resulting, e.g., in novel spin transistor concepts and novel insights regarding the so call persistent spin helix state. Ab-initio calculations provided a very effective tool to tackle complex problems from a fundamental quantum mechanical level and delivered dependencies which could be compared with experiment. Last but not least our expertise gained within the consortium has enabled us to quickly move into new emerging fields like the (spin) physics of 2D-materials, e.g., dichalcogenides. Also there we have made scientific contributions at the cutting edge of current research.
Publications
- Zero-bias spin separation. Nature Physics 2, 609 (2006)
S.D. Ganichev, V.V. Bel'kov, S.A. Tarasenko, S.N. Danilov, S. Giglberger, Ch. Hoffmann, E.L. Ivchenko, D. Weiss, W. Wegscheider, Ch. Gerl, D. Schuh, J. Stahl, J. De Boeck, G. Borghs, W. Prettl
(See online at https://doi.org/10.1038/nphys390) - Tunneling anisotropic magnetoresistance and spin-orbit coupling in Fe/GaAs/Au tunnel junctions. Phys. Rev. Lett. 99, 056601 (2007)
J. Moser, A. Matos-Abiague, D. Schuh, W. Wegscheider, J. Fabian, D. Weiss
(See online at https://doi.org/10.1103/physrevlett.99.056601) - All-Electrical Detection of the Relative Strength of Rashba and Dresselhaus Spin-Orbit Interaction in Quantum Wires. Phys. Rev. Lett. 101, 266401 (2008)
M. Scheid, M. Kohda, Y. Kunihashi, K. Richter, J. Nitta
(See online at https://doi.org/10.1103/physrevlett.101.266401) - Anisotropic tunneling magnetoresistance and tunneling anisotropic magnetoresistance: Spin-orbit coupling in magnetic tunnel junctions. Phys. Rev. B 79, 155303 (2009)
A Matos-Abiague, J Fabian
(See online at https://doi.org/10.1103/PhysRevB.79.155303) - Band-structure topologies of graphene: Spin-orbit coupling effects from first principles. Phys. Rev. B 80, 235431 (2009)
M. Gmitra, S. Konschuh, C. Ertler, C. Ambrosch-Draxl, J. Fabian
(See online at https://doi.org/10.1103/PhysRevB.80.235431) - Ferromagnetic GaAs/GaMnAS Core-Shell Nanowires Grown by Molecular Beam Epitaxy. Nano Lett. 9 3860 (2009)
A. Rudolph, M. Soda, M. Kiessling, T. Wojtowicz, D. Schuh, W. Wegscheider, J. Zweck, C.H. Back, E. Reiger
(See online at https://doi.org/10.1021/nl9020717) - Interference effects on the transport characteristics of a benzene single-electron transistor. Phys. Rev. B 79, 235404 (2009)
D. Darau, G. Begemann, A. Donarini, M. Grifoni
(See online at https://doi.org/10.1103/PhysRevB.79.235404) - Carbon Nanotubes as Cooper-Pair Beam Splitters. Phys. Rev. Lett. 104, 026801 (2010)
L. G. Herrmann, F. Portier, P. Roche, A. Levy Yeyati, T. Kontos, C. Strunk
(See online at https://doi.org/10.1103/physrevlett.104.026801) - Calculating condensed matter properties using the KKR-Green's function method-recent developments and applications. Rep. Prog. Phys 9, 096501 (2011)
H. Ebert, D. Koedderitzsch, J. Minar
(See online at https://doi.org/10.1088/0034-4885/74/9/096501) - Low-temperature photocarrier dynamics in monolayer MoS2. Appl. Phys. Lett. 99, 102109 (2011)
T. Korn, S. Heydrich, M. Hirmer, J. Schmutzler, C. Schüller
(See online at https://doi.org/10.1063/1.3636402) - Proximity Induced Enhancement of the Curie Temperature in Hybrid Spin Injection Devices. Phys. Rev. Lett. 107, 056601 (2011)
C. Song, M. Sperl, M. Utz, M. Ciorga, G. Woltersdorf, D. Schuh, D. Bougeard, C.H. Back, D. Weiss
(See online at https://doi.org/10.1103/physrevlett.107.056601) - Spin dephasing and photoinduced spin diffusion in a high-mobility two-dimensionl electron system embedded in a GaAs-(Al,Ga) As quantum well grown in the [110] direction. Phys. Rev. B 83, 241306 (2011)
R. Völkl, M. Griesbeck, S.A. Tarasenko, D. Schuh, W. Wegscheider, C. Schüller, T. Korn
(See online at https://doi.org/10.1103/PhysRevB.83.241306) - Universality of the Kondo Effect in Quantum Dots with Ferromagnetic Leads. Phys. Rev. Lett. 107, 176808 (2011)
M. Gaass, A. K. Hüttel, K. Kang, I. Weymann, J. von Delft, Ch. Strunk
(See online at https://doi.org/10.1103/physrevlett.107.176808) - Bulk electronic structure of the dilute magnetic semiconductor Ga1-xMnxAs through hard X-ray angle resolved photoemission. Nature Mater. 11, 957 (2012)
A.X. Gray, J. Minár, S. Ueda, P.R. Stone, Y. Yamashita, J. Fujii, J. Braun, L. Plucinski, C.M. Schneider, G. Panaccione, H. Ebert, O.D. Dubon, K. Kobayashi, C.S. Fadley
(See online at https://doi.org/10.1038/nmat3450) - Controlled Lateral Manipulation of Molecules on Insulating Films by STM. Nano Lett. 12, 1070 (2012)
I. Swart, T. Sonnleitner, J. Niedenführ, J. Repp
(See online at https://doi.org/10.1021/nl204322r) - Spin Transistor Action from Hidden Onsager Reciprocity. Phys. Rev. Lett. 108, 236601 (2012)
İ. Adagideli, V. Lutsker, M. Scheid, P. Jacquod, K. Richter
(See online at https://doi.org/10.1103/physrevlett.108.236601) - Spin-Transistor Action via Tunable Landau-Zener Transitions. Science 337, 324 (2012)
C. Betthausen, T. Dollinger, H. Saarikoski, V. Kolkovsky, G. Karczewski, T. Wojtowicz, K. Richter, D. Weiss
(See online at https://doi.org/10.1126/science.1221350) - Annealing-induced magnetic moments detected by spin precession measurements in epitaxial graphene on SiC. Phys. Rev. B 87, 081405 (2013)
B. Birkner, D. Pachniowski, A. Sandner, M. Ostler, T. Seyller, J. Fabian, M. Ciorga, D. Weiss, J. Eroms
(See online at https://doi.org/10.1103/PhysRevB.87.081405) - Sensor for Noncontact Profiling of a Surface. US patent 8,393,009, granted March 5 2013
F.J. Giessibl
- Sensor zum berührungslosen Abtasten einer Oberfläche. F.J. Giessibl, Patent DE 10 2010052037, granted April 18 2013
F.J. Giessibl
- Spin Resolution and Evidence for Superexchange on NiO(001) Observed by Force Microscopy. Phys. Rev. Lett. 110, 266101 (2013)
F. Pielmeier, F.J. Giessibl
(See online at https://doi.org/10.1103/physrevlett.110.266101) - Electrical Spin Injection into High Mobility 2D Systems. Phys. Rev. Lett. 113, 236602 (2014)
M. Oltscher, M. Ciorga, M. Utz, D. Schuh, D. Bougeard, D. Weiss
(See online at https://doi.org/10.1103/physrevlett.113.236602) - Graphene spintronics. Nature Nanotech. 9, 794 (2014)
W. Han, R.K. Kawakami, M. Gmitra, J. Fabian
(See online at https://doi.org/10.1038/nnano.2014.214) - Inverse spin Hall effect in Ni81Fe19/normal-metal bilayers. Phys. Rev. B 89, 060407 (2014)
M. Obstbaum, M. Härtinger, H. G. Bauer, T. Meier, F. Swientek, C.H. Back, G. Woltersdorf
(See online at https://doi.org/10.1103/PhysRevB.89.060407) - Spin Hall voltages from a.c. and d.c. spin currents. Nature Commun. 5, 3768 (2014)
D. Wie, M. Obstbaum, M. Ribow, C.H. Back, G. Woltersdorf
(See online at https://doi.org/10.1038/ncomms4768) - Spin relaxation mechanism in graphene: resonant scattering by magnetic impurities. Phys. Rev. Lett. 112, 116602 (2014)
D Kochan, M Gmitra, J Fabian
(See online at https://doi.org/10.1103/physrevlett.112.116602) - Broken SU(4) symmetry in a Kondo-correlated carbon nanotube. Phys. Rev. B 91, 155435 (2015)
D.R. Schmid, S. Smirnov, M. Margańska, A. Dirnaichner, P.L. Stiller, M. Grifoni, A.K. Hüttel, C. Strunk
(See online at https://doi.org/10.1103/PhysRevB.91.155435) - Graphene on transition-metal dichalcogenides: A platform for proximity spin-orbit physics and opto spintronics. Phys. Rev. B 92, 155403 (2015)
M. Gmitra, J. Fabian
(See online at https://doi.org/10.1103/PhysRevB.92.155403) - Sensor for Noncontact Profiling of a Surface. Chinese patent filing number 201110373640.4, granted August 6 2015
F.J. Giessibl
- Spin Hall effects. Rev. Mod. Phys 87, 1213 (2015)
Jairo Sinova, Sergio O. Valenzuela, J. Wunderlich, C. H. Back, and T. Jungwirth
(See online at https://doi.org/10.1103/RevModPhys.87.1213) - Subatomic resolution force microscopy reveals internal structure and adsorption sites of small iron clusters. Science 348, 308 (2015)
M. Emmrich, F. Huber, F. Pielmeier, J. Welker, T. Hofmann, M. Schneiderbauer, D. Meuer, S. Polesya, S. Mankovsky, D. Ködderitzsch, H. Ebert, F.J. Giessibl
(See online at https://doi.org/10.1126/science.aaa5329) - Control of spin helix symmetry in semiconductor quantum wells by crystal orientation. Phys. Rev. Lett. 117, 236801 (2016)
M. Kammermeier, P. Wenk, J. Schliemann
(See online at https://doi.org/10.1103/physrevlett.117.236801) - Deterministic transfer of spin polarization in wire-like lateral structures via the persistent spin helix. Appl. Phys. Lett. 109, 172106 (2016)
M. Schwemmer, A. Hanninger, M. Weingartner, M. Oltscher, M. Ciorga, D. Weiss, D. Schuh, D. Bougeard, T. Korn, C. Schüller
(See online at https://doi.org/10.1063/1.4966184) - Robust spin-orbit torque and spin-galvanic effect at the Fe/GaAs (001) interface at room temperature. Nature Commun. 7, 13802 (2016)
L. Chen, M. Decker, M. Kronseder, R. Islinger, M. Gmitra, D. Schuh, D. Bougeard, J. Fabian, D. Weiss, C. Back
(See online at https://doi.org/10.1038/ncomms13802) - Trion fine structure and coupled spin-valley dynamics in monolayer tungsten disulfide. Nature Commun. 7, 12715 (2016)
G. Plechinger, P. Nagler, A. Arora, R. Schmidt, A. Chernikov, A.G. del Aguila, P.C.M. Christianen, R. Bratschitsch, C. Schüller, T. Korn
(See online at https://doi.org/10.1038/ncomms12715) - Apparent reversal of molecular orbitals reveals entanglement. Phys. Rev. Lett 119, 056801 (2017)
P. Yu, N. Kocić, J. Repp, B. Siegert, A. Donarini
(See online at https://doi.org/10.1103/physrevlett.119.056801) - Femtosecond photo-switching of interface polaritons in black phosphorus heterostructures. Nature Nanotech. 12, 207 (2017)
M.A. Huber, F. Mooshammer, M. Plankl, L. Viti, F. Sandner, L.Z. Kastner, T. Frank, J. Fabian, M.S. Vitiello, T.L. Cocker, R. Huber
(See online at https://doi.org/10.1038/nnano.2016.261) - Gate-tunable large magnetoresistance in an all-semiconductor spin-transistor-like device. Nature Commun. 8, 1807 (2017)
M. Oltscher, F. Eberle, T. Kuczmik, A. Bayer, D. Schuh, D. Bougeard, M. Ciorga, D. Weiss
(See online at https://doi.org/10.1038/s41467-017-01933-2) - Nanotesla magnetoresistance in π-conjugated polymer devices. Phys. Rev. B 95, 241407(R) (2017)
P. Klemm, A. Schmid, S. Bange, J.M. Lupton
(See online at https://doi.org/10.1103/PhysRevB.95.241407) - Persistent Spin Textures in Semiconductor Nanostructures. Rev. Mod. Phys. 89, 011001 (2017)
John Schliemann
(See online at https://doi.org/10.1103/RevModPhys.89.011001) - Spectral focusing of broadband silver electroluminescence in nanoscopic FRET-LEDs. Nature Nanotech. 12, 637 (2017)
R.P. Puchert, F. Steiner, G. Plechinger, F. Hofmann, I. Caspers, J. Kirschner, P. Nagler, A. Chernikov, C. Schüller, T. Korn, J. Vogelsang, S. Bange, J.M. Lupton
(See online at https://doi.org/10.1038/nnano.2017.48) - Spin Physics in Semiconductors, ed. M.I. Dyakonov (Springer 2008) pp. 245-277. ISBN:3540788190 (second edition, extended, 2017, ASIN: B0765Z649V)
E.L. Ivchenko, S.D. Ganichev
(See online at https://doi.org/10.1007/978-3-540-78820-1_9) - Emergence of anisotropic Gilbert damping in ultrathin Fe layers on GaAs(001). Nature Phys. (2018)
L. Chen, S. Mankovsky, S. Wimmer, M.A.W. Schoen, H.S. Körner, M. Kronseder, D. Schuh, D. Bougeard, H. Ebert, D. Weiss, C.H. Back
(See online at https://doi.org/10.1038/s41567-018-0053-8)
