First-principles simulations of the stretching and final breaking of Al nanowires: Mechanical properties and electrical conductance

Jelı́nek, Pavel; Pérez, Rúben; Ortega, José; Flóres, F.

doi:10.1103/physrevb.68.085403

Cited by 70 publications

(73 citation statements)

References 30 publications

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“…4,19,24 A striking fact is that for values S m Ϸ 1 ͑defining a nanocontact of one-atom section͒ there are two different conductance values ͑G / G 0 Ϸ 2 and Ϸ1͒. We have confirmed that this fact is explained in terms of the presence of two different atomic arrangements 7 at the last stage of the breaking process. On the one hand, the monomer contact configuration ͓see Fig.…”

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confidence: 72%

“…But for monovalent alkali metals or polyvalent chemical species, single-atom contact studies revealed that this channel transmittivity can have a result smaller than one. 3,6,7 Nowadays, there exist several experimental techniques to characterize the electronic transport through nanocontacts. Among them, the measurement of the conductance histogram during nanocontact breakages [8][9][10] is one of the most used.…”

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confidence: 99%

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Ballistic resistivity in aluminum nanocontacts

et al. 2005

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We perform a representative series of semiclassical molecular dynamics simulations of aluminum nanocontact breakages, coupled to full quantum conductance calculations. This approach allows to obtain realistic conductance histograms of polyvalent species and understand the origin of their peaked structures. The results show that the conductance depends linearly on the contact minimum cross section for the geometrically favored nanocontact configurations. Valid in a broad range of conductance values, such relation suggests the definition of a transport parameter for the nanoscale, that represents the novel concept of ballistic resistivity. One of the major industrial challenges is to profit from some fascinating physical features present at the nanoscale. The production of dissipationless nanoswitches ͑or nanocontacts͒ is one of such attractive applications. 1 The inelastic electron mean free path is usually larger than nanocontact typical cross sections ͑of the order of few atoms in controlled experimets͒ even at room temperature, and, therefore, the electronic transport through these nanoconstrictions is expected to be ballistic. Nevertheless, the lack of knowledge of the real efficiency of this electronic ballistic/nondissipative transport limits future innovations.For contact sizes of the order of a few Fermi wavelengths F , well defined modes ͑channels͒ appear associated with the transversal confinement of electrons. For this situation, the conductance G is given by the Landauer formula G = G 0 ͚ n=1 N T n , where G 0 =2e 2 / h is the conductance quantum ͑e being the electron charge and h Planck's constant͒, T n is the transmission probability of the nth channel, and N is the number of propagating modes with energies below the Fermi energy. 2 It has been shown that the number of conducting channels is determined by the number of valence electrons of the respective chemical element. 3 For monovalent noble metals such as Cu, Ag and Au, the transmission probability T has been estimated to be approximately equal to 1 ͑i.e., each noble-metal atom contact contributes with G 0 to the conductance value 4,5 ͒. But for monovalent alkali metals or polyvalent chemical species, single-atom contact studies revealed that this channel transmittivity can have a result smaller than one. 3,6,7 Nowadays, there exist several experimental techniques to characterize the electronic transport through nanocontacts. Among them, the measurement of the conductance histogram during nanocontact breakages 8-10 is one of the most used. By putting in contact two opposite electrodes and then separating them, one observes a stepwise decrease in the electrical conductance ͑i.e., a conductance scan͒, until the breakpoint is reached. [11][12][13][14] It has been shown that each scan of the conductance dependence on the electrode retraction differs from one another, since the nanocontact structural evolutions during breakages are not identical. 15 Notwithstanding for fixed experimental parameter conditions ͑such as temperature and applied voltage...

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confidence: 99%

Ballistic resistivity in aluminum nanocontacts

et al. 2005

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“…However, measuring the mechanical and electrical properties of a nanowire is a difficult task due to the small dimensions [11]. In recent years, the deformation of nanowires have been studied by molecular dynamics simulations using either embodied-atom-method (EAM) [12][13][14][15] or effective-medium theory (EMT) [16,17] potentials as well as first-principles method based on the density functional theory (DFT) [18][19][20][21]. These studies focus on the correlation of the force (associated with the changes in the bonding of the nanowire) and the conductance for the metallic Au, Ni, and Na nano-contacts [17,22] and Au, Ni, Al, Na, and SiSe 2 nanowire [12,16,20,23].…”

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confidence: 99%

The uniaxial tensile deformation of Ni nanowire: atomic-scale computer simulations

Zhu

Shao

et al. 2005

Physica E: Low-dimensional Systems and Nanostructures

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The mechanical deformations of nickel nanowire subjected to uniaxial tensile strain at 300 K are simulated by using molecular dynamics with the quantum corrected Sutten-Chen many-body force field. We have used common neighbor analysis method to investigate the structural evolution of Ni nanowire during the elongation process. For the strain rate of 0.1%/ps, the elastic limit is up to about 11% strain with the yield stress of 8.6 GPa. At the elastic stage, the deformation is carried mainly through the uniform elongation of the distances between the layers (perpendicular to the Z-axis) while the atomic structure remains basically unchanged. With further strain, the slips in the {1 1 1} planes start to take place in order to accommodate the applied strain to carry the deformation partially, and subsequently the neck forms. The atomic rearrangements in the neck region result in a zigzag change in the stress-strain curve; the atomic structures beyond the region, however, have no significant changes. With the strain close to the point of the breaking, we observe the formation of a one-atom thick necklace in Ni nanowire. The strain rates have no significant effect on the deformation mechanism, but have some influence on the yield stress, the elastic limit, and the fracture strain of the nanowire. r

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“…For practical first-principles calculations this limit is very hard to realize due to the computational cost associated with an enlargement of the supercell and therefore relatively small supercells containing, e.g., 3 ϫ 3 atoms in the transverse plane are typically used as a compromise. 2,3,[6][7][8][9]11 A second approximation which is also commonly used, is to evaluate the transmission function only at the ⌫-point of the two-dimensional Brillouin zone ͑BZ͒ of the plane perpendicular to the transport direction. For example, this approximation has been applied in transport studies of Au ͑Ref.…”

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confidence: 99%

“…Many of these methods are based on a supercell approach where the system of interest is defined inside a finite computational cell which is then repeated periodically in the directions perpendicular to the transport direction while the appropriate open boundary conditions needed to describe the coupling to the electrodes are imposed in the parallel direction. [1][2][3][4][5][6][7][8][9][10][11] Within the supercell approach, one is obviously limited to consider transport through an infinite array of contacts, however, in practice this limitation is usually ignored. Whether the supercell approach can provide a good description of transport through a single, isolated contact depends on the degree of interference between the repeated images.…”

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Interference andk-point sampling in the supercell approach to phase-coherent transport

Thygesen

Jacobsen

2005

Phys. Rev. B

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We present a systematic study of interference and k-point sampling effects in the supercell approach to phase-coherent electron transport. We use a representative tight-binding model to show that interference between the repeated images is a small effect compared to the error introduced by using only the Γ-point for a supercell containing (3,3) sites in the transverse plane. An insufficient k-point sampling can introduce strong but unphysical features in the transmission function which can be traced to the presence of van Hove singularities in the lead. We present a first-principles calculation of the transmission through a Pt contact which shows that the k-point sampling is also important for realistic systems.

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First-principles simulations of the stretching and final breaking of Al nanowires: Mechanical properties and electrical conductance

Cited by 70 publications

References 30 publications

Ballistic resistivity in aluminum nanocontacts

Ballistic resistivity in aluminum nanocontacts

The uniaxial tensile deformation of Ni nanowire: atomic-scale computer simulations

Interference andk-point sampling in the supercell approach to phase-coherent transport

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