Spinorbit effects in carbonnanotube double quantum dots. An effectivemass hamiltonian is derived for carbon nanotubes in the presence of a weak spinorbit interaction. The dominant physical mechanism governing the intrinsic spinorbit interaction originates from d and higher carbon orbitals. Each year there will be four theory papers and one practical with aggregate marks. Spinorbit effects in carbon nanotube double quantum dots. Mechanical resonators based on a single carbon nanotube are exceptional sensors of mass and force. Electrical measurements of nano composite materials by using fourprobe method. For the twoelectron regime, the detailed structure of the spin orbit split energy spectrum is investigated as a function of detuning between the quantum dots in a 22dimensional hilbert space within the framework of a singlelongitudinalmode model. The nonobservation of an esr signal due to electrically induced charges is ascribed to the formation of tll states. Ultrasensitive displacement noise measurement of carbon. In fact, spin orbit interaction is important in curved graphene nanoribbons, since the induced spinsplitting on the edge states gives rise to spinfiltered states. Electron spin resonance on carbon nanotubespolymer composites. We use a fourorbital orthogonal tightbinding formalism to describe the electronic states and the random phase approximation to calculate the dielectric function. Spinorbit effects in carbon nanotubes analytical results.
Pdf josephson current in carbon nanotubes with spin. The novel nanostructures of carbon mildred dresselhausmildred dresselhaus. It has recently been recognised that the strong spinorbit interaction present in solids can lead to new phenomena, such as materials with nontrivial topological order. Spinorbit coupling and the static polarizability of single. Unit v introduction to carbon nano tubes cnts, properties, preparation of cntslaser ablation method, arc method, chemical vapor deposition cvd, solgel method, carbon nanotube polymer nano composites,applications of nano in drug delivery system. Spinorbit coupling in nearly metallic chiral carbon.
Spinorbit coupling in graphene structures 2012 kochan. For metallic carbon tubes, obviously, there is the fourfolddegenerate electronic energy spectrum at the fermi wave vector without any so coupling interaction, shown by the blue lines in fig. Since the spinorbit interaction in graphite is very small, the spin lifetime in graphene can be very long. Spinorbit interaction in carbon nanotubes has been under debate for several years and a variety of theoretical calculations and experimental results have been. Spinorbit interaction in single wall carbon nanotubes. If spinorbit interactions lead to the decay of spin signals, you might expect mceuen and colleagues results 1 to rule out carbon nano tubes as a medium for spintronics devices. For example, we have developed a scheme for implementing the cnot gate over qubits encoded in a pair of electron spins in a double quantum dot. Spin states and spinorbit coupling in nanostructures ferdinand kuemmeth, ph. Josephson current in carbon nanotubes with spinorbit interaction jong soo lim,1 rosa lo. Although the atomic spinorbit coupling in carbon is weak, the spinorbit coupling in carbon nanotubes can. Spinorbit interaction in a twodimensional electron gas. Electrically induced ambipolar spin vanishments in carbon. The obtained results indicate that weak rashba spinorbit coupling interaction can lead to the breaking of fourfold degeneracy in all tubes even though without the intrinsic so coupling. Since the spinorbit splitting of a carbon atom has been expected to be a few millielectron volt,2933 the e.
Spinorbit coupling and proximity effects in metallic carbon nanotubes. Josephson current in carbon nanotubes with spinorbit. In the case of graphene monolayer, the intrinsic spinorbit coupling opens a gap of 24 ev at the kk. At the heart of this lies the spin orbit interaction soi, a relativistic effect that is responsible for many fascinating phenomena discovered recently, such as topological insulators, majorana fermions, spin effects in strongly correlated materials and. The spinorbit interaction gives rise to terms corresponding to a kind of a spinzeem. We further present detailed microscopic properties of atomic vacancies, such as spin concentration, spinlattice relaxation time, motion of vacancies, and anisotropy of spinorbit interaction in the swcnt thin film.
Spinorbit coupling and proximity effects in metallic carbon. Cv of yshai avishai personal details date and place of birth. For the twoelectron regime, the detailed structure of the spinorbit split energy spectrum is investigated as a function of detuning between the quantum dots in a 22dimensional hilbert space within the framework of a singlelongitudinalmode model. We find a competing effect of the tunneling and coulomb interaction. Tunable fewelectron double quantum dots and klein tunnelling. The presence of spinorbit interaction a result of the nano tube curvature allows electrical control of the electron spins 2, 3, which can be read out in nanotube double. The spinorbit interaction gives rise to terms corresponding to a kind of a spinzeeman energy due to magnetic fields in the circumference and axis direction. In carbon nanotubes, there are two contributions to the spinorbit coupling, one which we describe as orbitaltype coupling, which induces a shift. Pdf spinorbit interaction in bent carbon nanotubes. Electron spin resonance on carbon nanotubespolymer.
We show the importance of chirality, curvature and familydependent behaviour in these systems. We study the energy spectrum of symmetric double quantum dots in narrowgap carbon nanotubes with one and two electrostatically con. Spinorbit interaction can be understood as an effective exchange. Curvature effects in the band structure of carbon nanotubes. Microwave spectroscopy of a carbon nanotube charge qubit. Josephson effect in carbon nanotubes with spinorbit coupling. In this work, we consider single wall carbon nanotubes helically wrapped with single stranded polyt dna. A model for the spinorbit interaction in graphite as imposed by symmetry was developed g. This is no longer the case once the graphene plane is folded into the cnt 912, for which the effect of spinorbit coupling are clearly observed. The force sensitivity in these ultralight resonators is often limited by the noise in the detection of the vibrations. The spin orbit interaction gives rise to terms corresponding to a kind of a spin. Here, we report on an ultrasensitive scheme based on a rlc resonator and a lowtemperature amplifier to detect nanotube vibrations. Adsorption energies for linear and dumbbell lead nanowires in di.
Coupling of spin and orbital motion of electrons in carbon. Energy band for single wall carbon nanotubes with spinorbit interaction is calculated using non orthogonal tightbinding method. For atoms of low atomic number, the spinorbit coupling is a relatively small correction to the energy, but. Rohilkhand university, bareilly course structure for m. We study the role of both the rashba as well as the intrinsic spinorbit. Hidden fine structure of quantum defects revealed by. Prolonged spontaneous emission and dephasing of localized. Cornell university 2008 this dissertation describes electronic transport measurements which we performed on two di erent nanoscale systems. Summary coherent interaction between the spins of ferromagnets and femtosecond laser pulses p. The anisotropy in the induced spinsplitting in chiral nanotubes and ribbons is directly related to. Due to light carbon atoms in the sp2 lattice, swcnts exhibit a weak spin. Josephson current in carbon nanotubes with spinorbit interaction.
Spinorbit interaction in carbon nanotubes journal of the physical. As is wellknown in graphenes and carbon nano tubes,1115 electrons, whose motion is described by weyls equation for a neutrino or the dirac equation. One reason why this works so well is that the spinorbit interaction in the nanotubes studied by pei and colleagues 4 is stronger than in tubes investigated earlier, for reasons that at this. Pdf carbon nanotubes in electric and magnetic fields. Tunable fewelectron double quantum dots and klein tunnelling in ultraclean carbon nanotubes g.
As a result we obtain a simple description of the interplay of the two types of spinorbit interaction, and a physically transparent explanation of the vanishing of the d. Spin physics plays a fundamental role in many fields of modern condensed matter, notably for spintronics and spin based quantum computation. Mceuen laboratory of atomic and solid state physics, department of physics, cornell university, ithaca ny 14853 these authors contributed equally to this work electrons in atoms possess both spin and orbital degrees of freedom. Spin orbit interaction is also of a great use for the manipulation of spin states in quantum dots. Solid state communications 152 2012 14771482 contents lists. Fanoresonance analysis hojin cho, hyun young jung1, qhan park2, jung sang suh1 and wonho jhe school of physics and center for near. From these results, we conclude that sites that are preferentially found in end caps provide more active electronic states for the chemi cal interaction. Jan 01, 2011 we explore the band structures of singlewalled carbon nanotubes swcnts with two types of spinorbit couplings. Pdf intrinsic spinorbit interaction in carbon nanotubes and. An effectivemass hamiltonian is derived for carbon nanotubes in the presence of a weak spin orbit interaction. The spinorbit interaction gives rise to terms corresponding to a kind of a spin.
Intrinsic spinorbit interaction in carbon nanotubes and. Spin states and spin orbit coupling in nanostructures ferdinand kuemmeth, ph. Spinorbit coupling and the static polarizability of. It has been postulated that spin polarization should increase with the length of the wrapped tubes. Theory of magnetic response in twodimensional giant. Recently, it has been reported that carbon nanotubes, helically wrapped with dna, can also act as an efficient source and detector of spinpolarized carriers, by virtue of spinorbit coupling originating from the helical potential. Spinorbit coupling in nearly metallic chiral carbon nanotubes. Here we extend our study to the nonplanar geometries of carbon nanotubes, analyzing different tube chiralities and extending our symmetry. Spinorbit coupling and proximity effects in metallic.
Blockade at a different level nature nanotechnology. Curvatureinduced orbital hybridization is crucial to understand the experimentally observed anisotropic spin orbit splittings in carbon nanotubes. Structural and electronic properties of bismuth and lead. Size effect, quantum confinement, fullerines and carbon nano tubes, single wall and multi wall carbon nanotubes, mechanical and electronic properties of carbon.
Large spinorbit coupling in carbon nanotubes nature. We study the spinorbit coupling in metallic carbon nanotubes cnts within the manybody tomonagaluttinger liquid framework. Physics with specialization in electronics this is a twoyear course. As a result, the fourfold degeneracy breaks into two kramers doublets timereversed electrons pairs. Intrinsic spinorbit interaction in carbon nanotubes and curved nanoribbons. Spinorbit interaction in carbon nanotubes journal of. Theoretical condensed matter physics, low dimensional systems, carbon nano tubes, graphene and the other 2d structures, electronphonon interaction, spinorbit interaction, density functional theory, string theory and extra dimensions, standard model, lie group analysis and symmetries of partial di erantial equations.
Energy spectra and transport properties of armchair nanotubes with curvature induced spin orbit interaction are investigated thoroughly. In particular, they have unique properties that make. The kanemele model was previously used to describe effective spinorbit couplings socs in graphene. Compared to gaas quantum dots, the spectrum exhibits a much richer structure because of the spinorbit interaction that. Theory of magnetic response in twodimensional giant rashba. Spin orbit interaction and majorana fermions in carbon. It is found that the both terms are equally important. We develop an effective tightbinding hamiltonian for spin orbit so interaction in bent carbon nanotubes cnt for the electrons forming the. We further present detailed microscopic properties of atomic vacancies, such as spin concentration, spin lattice relaxation time, motion of vacancies, and anisotropy of spin orbit interaction in the swcnt thin film. The scheme is based on exchange and spin orbit interactions and on local gradients in zeeman. As a result spin scattering is induced even by spinindependent scatterers. This is experimentally relevant because quantum crossbars can be fabricated from carbon nano tubes.
Closed carbon nanotubes cnts show larger amounts of absorption for gases such as hydrogen, he, ne and ar than opened cnts. Dec 31, 2018 recently, it has been reported that carbon nanotubes, helically wrapped with dna, can also act as an efficient source and detector of spinpolarized carriers, by virtue of spinorbit coupling originating from the helical potential. Pdf spinorbit effects in carbon nanotubes analytical results. But the interaction isnt strong enough to cause insurmountable problems. Experimental evidence for spin orbit coupling in carbon nanotubes. As a result we obtain a simple description of the interplay of the two types of spin orbit interaction, and a physically transparent explanation of the vanishing of the d. We calculate the static longitudinal polarizability of singlewall carbon tubes in the long wavelength limit taking into account spinorbit effects. The main question is whether bosonization techniques are still applicable and.
Hidden fine structure of quantum defects revealed by single. Mar 27, 2008 a, electrons confined in a nanotube segment have quantized energy levels, each fourfold degenerate in the absence of spinorbit coupling and defect scattering. Pdf energy spectra and transport properties of armchair nanotubes with curvature induced spinorbit interaction are investigated thoroughly. Spin physics plays a fundamental role in many fields of modern condensed matter, notably for spintronics and spinbased quantum computation. It has recently been recognized that the strong spinorbit interaction present in solids can lead to new phenomena, such as materials. Although the atomic spinorbit coupling in carbon is weak, the spinorbit coupling in carbon nanotubes can be signi. Maslyuk,a rafael gutierreza and gianaurelio cunibertiabc spinorbit interaction in carbon nanotubes has been under debate for several years and a variety of theoretical calculations and experimental results have been published. Coupling of spin and orbital motion of electrons in carbon nanotubes f. Mwcnt has a good conductivity even though its occupied portion of the waveguide was very small. Band structures of carbon nanotube with spinorbit coupling.
By magnetoresistance measurements we show that this system exhibits significant spin polarization of. Recently, the use of spinpolarized graphene has also attracted much attention 11. Highlights we have studied intrinsic spinorbit interactions in carbon nanotubes and curved graphene ribbons. Spinorbit interaction in bent carbon nanotubes iopscience. Here we extend this model and also incorporate curvature effects to analyze the combined influence of soc and curvature on the band structure of carbon nanotubes cnts. This, on one hand, could provide desirable long spin coherence, but makes figure 1. Energy spectra and transport properties of armchair nanotubes with curvature induced spinorbit interaction are investigated thoroughly. For this reason, the use of this material was very ideal for comparison of the. Electron spins in carbon nanotube quantum dots are therefore attractive for implementation of a quantum bit. The manipulation of the spinpolarized current can be done by.