Mule Usually, depending upon the relative orientation of magnetization in the magnetic contact layers the circuit resistance changes from minimum resistance for the parallel magnetization P to maximum resistance for the anti-parallel magnetization AP between the contacts resulting in a spin-valve effect [ — ]— The foundation behind modern high density data storage devices. Theory of graphitic boron nitride nanotubes. Molecular orbital analysis shows the frontier orbital characters particularly at the interface are different for the P and AP configurations. Nitrogen in graphite and carbon nanotubes: For a semiconducting channel, the relative resistance between the P and AP configurations is known as tunnel leey resistance TMR [ 49 ]. Bandgap modulation of narrow-gap carbon nanotubes in a transverse electric field.
|Published (Last):||23 June 2006|
|PDF File Size:||11.26 Mb|
|ePub File Size:||1.85 Mb|
|Price:||Free* [*Free Regsitration Required]|
Totaxe Transformation from chemisorption to physisorption with tube diameter and gas concentration: Conflicts of Interest The authors declare no conflict of interest. The different responses of BNNTs and semiconducting CNTs to the transverse electric field are attributed to ly different bonding features. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, ldy exciting opportunities to sustain the current growth in the information industry.
Are fluorinated boron nitride nanotubes n -type semiconductors? Radial deformation and its related energy variations of single-walled carbon nanotubes. Support Center Support Center. In addition, like CNTs [ — ], BNNTs have also been explored as potential materials for hydrogen storage [ — ]; nanotubes have been demonstrated to retain 1.
Implication for nano-spintronic devices. The adsorptions of these different atoms and molecules introduce impurity states within the band gap of BNNT [ 43, — ]. Acknowledgments Some of the calculations presented here were obtained using RAMA and Superior, the high performance computing clusters at Michigan Technological University. Besides, F-BNNT has been shown to have high conductivity [ 25 key, which makes it an ideal candidate for a spin filter. Pressure-induced ferromagnetism in In, Mn Sb dilute magnetic semiconductor.
Theory of graphitic boron nitride nanotubes. An important finding of this work [ ] is that although the interaction between BN layer and PTAS is of the van der Waals type, the band structure of the physisorbed system is different from the superposition of the band structures of the BN layer and the PTAS adsorbate. Young modulus, mechanical and electrical properties of isolated individual and bundled single-walled boron nitride nanotubes.
A density functional theory study. First, the location of the spin-down sub-band in the device is closer to the Fermi energy than the spin-up sub-band. Metal particle catalysed production of nanoscale BN structures. Adsorption hydrogen molecules on the platinum-doped boron nitride nanotubes.
BNNT as a Spin Filter A spin filter allows all majority or minority spin carriers to pass through the channel while the minority or majority spin carriers, which requires splitting of spin components. Similarly, B adsorption on BNNTs is reported to induce magnetism, which is found to be independent of the tube diameter [ ]. It also offers higher resistance to oxidation [ ] and a higher thermal stability [ 11 ] in comparison to CNTs. Coherent transport of electron spin in a ferromagnetically contacted carbon nanotube.
The change in sign of J is attributed to the electric field-induced modification of magnetic exchange interactions at the interface [ ] see the inset of Figure 10d by the Stark effect [ 55 ]. Defect-originated magnetism in carbon-based and non-traditional inorganic compounds: Electronic and magnetic properties of a BN sheet decorated with hydrogen and fluorine.
Electronic structure analysis shows that there is an asymmetry in the density of states between the spin lry and spin down branches at the Fermi energy giving rise to magnetism in the F-BNNT with a net magnetic moment of 0. Pronounced resistance to oxidation.
National Center for Biotechnology InformationU. It has been reported that the metal-free fluorinated BNNT exhibits long range ferromagnetic spin ordering, which is stable at a temperature much higher than room temperature. The large le gap of the BNNT limits in some leu its direct application in electronics. Electrical contacts to one- and two-dimensional nanomaterials.
A simple approach to covalent functionalization of boron nitride nanotubes. A strong charge transformation happens in between adsorbates and BNNTs during the chemisorption, which makes covalently functionalized BNNTs either a p-type or an n-type semiconductor, depending upon the electronegativity of the adsorbates . Electric Field as an External Stimulus One of the possible ways of tuning band gap of BNNTs is by using a transverse electric field, which breaks the symmetry of the electronic states in the direction of applied field and mixes the nearby sub-bands in the conduction band complex and the valance band complex separately [ 21 ].
Spintronics, which requires controlled transport of spin polarized carriers, has been explored in low let materials such as organic molecules [ 47 — 53 ], graphene [ ], and CNTs [ 56 — 59 ]. Sorting carbon nanotubes by electronic structure using density differentiation. Figure 9 shows the band structure of pristine and fluorinated 6, BNNTs; new energy levels for both the up and down spin states having relatively small dispersion appear close to the Fermi energy upon the adsorption of F pey BNNTs.
Tuning the electronic properties of boron nitride nanotubes with transverse electric field: Engineering of electronic structure of boron-nitride nanotubes by covalent functionalization. Significant leh in their electronic structure is expected under a strong deformation within the elastic limit. Traditionally, the formation of local magnetic moments in different elements and alloys has been associated with partially filled d and f states of the elements [ — ]; collective magnetism in such materials is the result of coupling between these localized moments.
An ab Initio Study. The functionalization in which hybridization at the adsorption site of the host remains unchanged upon functionalization is called non-covalent physisorption functionalization [ ].
This effect is diameter dependent; a bigger diameter BNNT exhibits a stronger response to the transverse electric field in comparison to a smaller diameter tube [ 21 ]. This suggests that the open-ended BNNT could possibly be used as spin polarized electron field emitters [ 44 ].
Boron Nitride Nanotubes for Spintronics The second point is that the spin-down orbital coupled more strongly to the metal state at the interface than the spin-up orbital; this increases the broadening and the escape rate of the spin-down electrons as seen from Figure 11b [ 30 ]. Both the static magnetism and magneto-transport properties in BNNT junctions are highlighted.
For example, Wang et al. The partially filled bands near the Fermi-energy in the case of fluorinated BNNT have small dispersion as the fluorine atom acts as shallow acceptor upon adsorption on BNNT. Thus far, we have reviewed static magnetism associated with BNNTs. The chiral indices m, n denote the number of unit vectors lej two directions in the honeycomb 2D hexagonal BN lattice.
Reversible band-gap engineering in carbon nanotubes by radial deformation. TOP 10 Related.
La Ley de Gestión Integral de Residuos Industriales y de Actividades de Servicios
Presidкncia da Repъblica