We illustrate our findings by analyzing the response of interacting spin chains to a rotating magnetic field. Fig. The quantum Hall effect is a well-accepted theory in physics describing the behavior of electrons within a magnetic field at extremely low temperatures. The transition between the spin-polarized (with fill fraction ν = 1/3) and spin-unpolarized (ν = 2/5) states is accompanied by a complicated series of hysteresis loops reminiscent of a classical ferromagnet. Introduction. We studied the breakdown of the quantum Hall state in graphene with two-fold motivation. 1d and e), which can be probed by scanning tunneling microscopy. This is a course on the quantum Hall effect, given in TIFR, Mumbai. In 2005, Kane and Mele discovered in graphene a topological phase known as the quantum spin Hall effect . Today: Device Characterization by low-temperature magneto-transport It is a simple consequence of the motion of charged particles in a magnetic eld. Hall Effect Measurement in Germanium (Electrical Transport Option) Prof. Richard Averitt, UC San Diego . Quantum Hall Effect. Quantum Hall state • simplest example: noninteracting electrons filling n Landau levels (interger QH effect) • Fractional QH effect: much more complicated theory (Laughlin) • gapped, no low-energy degree of freedom • The effective action can be expanded in polynomials of external fields • To lowest order: Chern-Simons action S = 4 d3 xµ A µ A encodes Hall conductivity Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. B. Spielman Joint Quantum Institute, National Institute of Standards and Technology and Department of Physics, University of Maryland, Gaithersburg, MD 20899, USA Introduction to spin Hall effect w The quantum Hall effect: experimental data¶. σ = ne2/h. Eventually the time dependence will cease. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. 8) Conclusion . Full Text HTML; Download PDF 7) Topological Quantum Computation . Quantum anomalous Hall effect—the appearance of quantized Hall conductance at zero magnetic field—has been observed in thin films of the topological insulator Bi2Se3 doped with magnetic atoms. High Attention Score compared to … Recently, the quantum Hall e ect (QHE) has been observed in graphene [1, 2] and studied extensively [3]. Spin polarization of the quantum spin hall edge states. In the original experiment, silver atoms were sent through a spatially varying magnetic field, which deflected them before they struck a detector screen, such as a glass slide. (Right) The quantum anomalous Hall effect has quantum Hall features without an applied field. The “free-electron quantum gas” model still predicts a hall coefficient of 1/nq and zero magnetoresistance [5]. University of Basel Magnonic Quantum Hall Effect & the Wiedemann-Franz Law Kouki Nakata KN, J. Klinovaja & D. Loss, arXiv:1611.09752 (2016) All the responsibilities of this slide rest with Kouki Nakata (Jan. 2017) See also [KN, P. Simon, and D. Loss: Phys. Magnetism, when combined with an unconventional electronic band structure, can give rise to forefront electronic properties such as the quantum anomalous Hall effect, axion electrodynamics, and Majorana fermions. Experiments on a nearly spin degenerate two-dimensional electron system reveals unusual hysteretic and relaxational transport in the fractional quantum Hall effect regime. 5) Conformal field theory constructions . For a short introduction, see also N. Read, Physics Today, July 2012, p. 38 Quantum Spin Hall Effect • The QSH state can be thought of as B eff two copies of QH states, one for each spin component, each seeing the opposite magnetic field. Charge transport and nanoelectronics. Giuseppe Maruccio A quantum twist on classical optics. The quantum anomalous Hall (QAH) effect, considered as a quantized version of anomalous Hall effect discovered in 1881 , has been theoretically proposed for magnetic topological insulators (TIs) [8–13], where the ferromagnetic ordering and spin–orbit coupling (SOC) are sufficiently strong that they can give rise to a topologically non-trivial phase with a finite Chern number. Each electron, until it is measured, will Via per Arnesano, 73100, Lecce (Italy) B 92, 134425 (2015)] 3D quantum Hall effect relies on the charge density wave (CDW), which may gap the 1D Landau band so that the bulk is insulating. Typical experimental data looks like this (taken from M.E. Giuseppe Maruccio Fractal Quantum Hall Effect (-3, 1) R xx (kW) 0 15 Temperature Dependence Fractal Gap Size 83 K . SUBMITTED TO: Prof. R.S SINGH Now customize the name of a clipboard to store your clips. JNVU (Department of Physics). (2000) Buhmann (2011) 7. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. See our User Agreement and Privacy Policy. The quantum Hall effect can also be regarded as an appealingly straightforward precision measurement of the fine-structure constant, e 2 /ħc, yielding a value of 1/137.0360 0300(270). 0" from states with electron character ! Via a ``wormhole'' tunneling assisted by the Weyl nodes, the Fermi arcs at … The quantum Hall effect (QHE) and its relation to fundamental physical constants was discovered in 1980 by Klaus von Klitzing for which he received a Nobel prize in 1985. The spin Hall effect in a quantum gas M. C. Beeler*, R. A. Williams, K. Jimenez-Garcia, L. J. LeBlanc, A. R. Perry, I. The essence of the quantum spin Hall effect in real materials can be captured in explicit models that are particularly simple to solve. Quantum Hall effect of 2D Bloch electrons in a periodic potential Conductivity for finite time Conductivities oscillate in short time. Quantum transport: Transport regimes and mesoscopic quantum transport, Scattering theory of conductance and Landauer-Buttiker formalism, Quantum point contacts, Quantum electronics and selected examples of mesoscopic devices (quantum interference devices). j. y = 0 → the transverse field (the Hall field) E. y. due to the accumulated charges . Quantum Hall effect • quantized states of Hall resistance appear • attributed to spin density transitions • Landau levels Schön et al. Molecular electronics: Donor-Acceptor systems, Nanoscale charge transfer, Electronic properties and transport in molecules and biomolecules; single molecule transistors. Our observed magnetotransport features are comparable to those observed for typical exfoliated graphene samples [ 36 ] and high-quality CVD-graphene samples [ 40 , 41 ]. Experimental observation of the spin-Hall effect in a two dimensional spin-orbit coupled semiconductor system 1. II. If you continue browsing the site, you agree to the use of cookies on this website. 30 T). Half-integer quantum Hall effect in graphene Exceptionally high mobility graphene samples allow us to investigate transport phenomena in the magnetic quantum limit where the QHE manifests itself. E k n=1 n=2 n=3 n=4 n=5 n=0 Figure 12: Integer quantum Hall e↵ect Figure 13: Landau levels At the end of the 1970’s researchers used extremely low temperatures (only a few degrees from absolute zero, i.e. Christoph Brüne, Andreas Roth, Hartmut Buhmann, Ewelina M Hankiewicz, Laurens W Molenkamp, Joseph Maciejko, Xiao-Liang Qi, and Shou-Cheng Zhang. The Quantum Hall effect (QHE) is the observation of the Hall effect in a two-dimensional electron gas system (2DEG) such as graphene and MOSFETs. !# 0". Hall effect measurements in organic semiconductors Edward Burt Driscoll Paralleling the use of Hall effect measurements used in inorganic conductors … Quantum Hall Effect. In real space, the CDW splits the 3D Fermi energy Energy x B B k Charge density wave 2D 3D Energy x y FIG. quantities of interest: ... Slide 1 Last modified by: The alternative of measuring the electron’s anomalous magnetic moment does give the fine-structure constant with somewhat greater precision. Rev. The quantum numbers to be manipulated are the spin index, valley index, and layer index in multilayer systems, measured at low temperatures and high magnetic fields where Luttinger liquids, quantum Hall ferromagnets, and multi-valley systems can be probed. famous Quantum Hall Effect4. In the presence of a magnetic field, the electron may exist in two possible spin states, usually referred to as spin up and spin down. B • QHE (especially integer) is robust-Hall resistance Rxy is quantized even in very messy samples with dirty edges, not so high mobility. Instead, a completely unexpected result was measured for the first time by Klaus von Klitzing. Science, 314(5806):1757–1761, 2006. 2-D system, perpendicular magnetic field. in equilibrium . The carrier Hall mobility of hexagonal boron nitride (hBN) encapsulated InSe flakes can be up to 5000 cm 2 V −1 s −1 at 1.5 K, enabling to observe the quantum Hall effect in a synthesized van der Waals semiconductor. J. Weis, in Encyclopedia of Condensed Matter Physics, 2005. Looks like you’ve clipped this slide to already. Quantum Hall effect, quantum transport Y. Ji et al., Nature 422 (2003) 415. EFFECT Scanning Probe Microscopy M. A. Topinka et al., Science 289 (2000) 2323. See our Privacy Policy and User Agreement for details. SUBMITTED BY: VISHAL KUMAR JANGID,M.Sc(Final) 2016-17 Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Quantized values of Hall Conductivity. It represents good example of physical systems where quantization effect could be observed microscopically as a result of the interplay of the topology, interactions of electron with magnetic field, electron-electron interactions, and disorder. Clipping is a handy way to collect important slides you want to go back to later. It is the "coupling constant" or measure of the strength of the electromagnetic force that governs how electrically charged elementary particles (e.g., electron, muon) and light (photons) interact. Electronic properties of nanomaterials, Customer Code: Creating a Company Customers Love, Be A Great Product Leader (Amplify, Oct 2019), Trillion Dollar Coach Book (Bill Campbell), No public clipboards found for this slide, II_Quantum Hall Effects&Quantum Transport. This means you're free to copy and share these comics (but not to sell them). Two groups have now observed quantum anomalous Hall effect in intrinsically magnetic … Edwin Herbert Hall (1879): discovery of the Hall effect. The fractional quantum Hall effect has been one of the most active areas of research in quantum condensed matter physics for nearly four decades, serving as a paradigm for unexpected and exotic emergent behavior arising from interactions. This will provide a useful background for our discussion of the quantum Hall e ect. Jesse Noffsinger ; Group Meeting Talk (As required by the Governor of the State of California) April 17, 2007; 2 Classical Hall Effect Experimental Values B Metal RH (-1/nec) Li 0.8 Na 1.2 Rb 1.0 Ag 1.3 Be -0.2 Ex, jx VH Ey - - - - - - - - - - - - - - - - - - … Systems of interest are quantum wires, quantum wells, and quantum Hall effect. David Tong: Lectures on the Quantum Hall Effect. Does not depend on material or impurities or geometry. Quantum spin Hall effect in semiconductor quantum wells [Bernevig, Hughes, Zhang, Science 314, 1757 (2006)] Quantum spin Hall effect in 2D topological insulator HgTe quantum well [Koenig et al., Science 318, 766 (2007)] Observation of QSHE in quantum wells [Du et al.,PRL 114 (2015) 096802] Quantum Hall Effect: 2D electron gas (2DEG) in magnetic field, Landau levels, de Haas-van Alphen and Shubnikov-de Haas Effects, integer and fractional quantum Hall effects, Spin Hall Effect. The Stern–Gerlach experiment demonstrated that the spatial orientation of angular momentum is quantized.Thus an atomic-scale system was shown to have intrinsically quantum properties. Magnonic Quantum Hall Effect & the Wiedemann-Franz Law 1. the Lorentz force. The extracted quantum mobility is about five times smaller than the Hall and field effect mobilities and characterizes the effective broadening of the Landau levels due to disorder. CNR NANOTEC - Institute of Nanotechnology Suddards, A. Baumgartner, M. Henini and C. J. Mellor, New J. Phys. balances the Lorentz force. world of 2d electrons is exciting modulation doping – high purity enables ‘ballistic transport’ – easy electrostatic control gates close to surface – unique excitations (e.g., fractional statistics) Aharonov-Bohm effect in graphene Fabry Pérot quantum Hall Interferometers Yuval Ronen 1† , Thomas Werkmeister 2† , Danial Najafabadi 1 , Andrew T. 1Pierce 1 , Laurel E. Anderson , Young J. Shin 3 , Si Young Lee 4 , 4Young Hee Lee , Bobae Johnson 1 , Kenji Watanabe 5 , Takashi Taniguchi 6 , The quantum Hall effect continues to reveal its secrets to mathematicians and physicists. QUANTUM HALL giuseppe.maruccio@unisalento.it Clipping is a handy way to collect important slides you want to go back to later. The quantum anomalous Hall effect is a novel manifestation of topological structure in many-electron systems and may have ...Read More. Introduzione Nanoscienze e Nanotecnologie. The fundamental quantum of Hall resistance is h/e2 =25,813Ω. Complex effects in condensed-matter systems can often find analogs in cleaner optical systems. Outline Introduction: Modular invariance in FQHE Review: Dyonic Black Holes and Modular Invariance SL(2,Z) and the Real-Analytic Eisenstein Series Note that there will be a Landau level at zero energy that separates states with hole character !!" 1. and electromechanical properties in a resonator geometry. 2005: Quantum Spin Hall Effect/Z 2 topological insulator Bernevig and Zhang, 2006 helical)edge)states Energy)spectrum) (for)one)edge)) Experimental observation of HgTe TI Introductory idea of integral & fractional quantum hall effect and by imposing the idea of composite fermions showing the existence of fractional charge. Science 289 ( 2000 ) 2323 and to provide you with relevant advertising ( but not to them... Ρ x y ) takes on quantized values while the longitudinal resistance ( x... 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