Current-induced transition in atomic-sized contacts of metallic alloys

Heemskerk, Jan W T; Noat, Yves; Bakker, David; Ruitenbeek, J. M. van; Thijsse, Barend J.; Klaver, Peter

doi:10.1103/physrevb.67.115416

Cited by 35 publications

(26 citation statements)

References 20 publications

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“…As to Joule heating, the temperature rise in a nanocontact due to electron energy dissipation is still a matter of controversy [1], and no definite results have been established on the contact temperature under high-bias/high-current conditions. On the other hand, electromigration of atoms have been experimentally observed in atom-sized contacts under high biases [8,9], and two-level fluctuations (TLF) in conductance were reported on some metal nanocontacts at low temperatures [8,10,11]. Although these previous observations of TLF suggest that our conductance fluctuations are likely due to electromigration, no detailed analyses can be made at this time since electromigration is a thermally activated process but we lack information on the contact temperature.…”

Section: Discussionmentioning

confidence: 51%

Stability of Atom-sized Metal Contacts under High Biases

Fujii

Mizobata

Kurokawa

et al. 2004

e-J. Surf. Sci. Nanotechnol.

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Conductance and its bias dependence have been measured on Au and Ag breaking nanocontacts for biases up to 3.0 V at room temperature in ultrahigh vacuum. Under high-bias/high-current conditions, both Au and Ag contacts often show a characteristic conductance fluctuation when the conductance attains a certain critical value Gth. This critical conductance ranges from ∼ 10G0 to ∼ 50G0 (G0 ≡ 2e 2 /h is the quantum unit of conductance) and increases with the bias. When Gth is plotted against the contact current I, we obtained a linear I − Gth plot for Au contacts. Since Gth is in a semiclassical regime and hence should be proportional to the cross sectional area of the contact, the slope of the I − Gth plot represents a critical current density for the onset of the conductance fluctuation. These observations indicate that the conductance fluctuation is due to certain current-induced contact instability. When the current density exceeds the critical value, a contact becomes unstable and tends to be ruptured, leaving small chances of further necking deformation down to a single-atom contact.

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Section: Discussionmentioning

confidence: 51%

Stability of Atom-sized Metal Contacts under High Biases

Fujii

Mizobata

Kurokawa

et al. 2004

e-J. Surf. Sci. Nanotechnol.

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“…the conductance becomes either G A or G B when A or B atom occupies the contact site. This "locality" of the alloy SAC conductance has been clearly demonstrated by Heemskerk et al [24] who showed that the Au-like conductance histogram of AuPt changes to the Pt-like one when a Pt atom migrates to the contact site. If a similar locality holds for the break voltage of AuAg SACs, it would be either V b,Au or V b,Ag depending on whether the contact atom is Au or Ag.…”

Section: Introductionmentioning

confidence: 57%

Break Voltage of the 1G0 Contact of Noble Metals and Alloys

Miura

Iwata

Kurokawa

et al. 2009

e-J. Surf. Sci. Nanotechnol.

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We have measured the break voltage of the 1G0 contact of Au, Ag, Cu, and AuAg alloys at room temperature in ultrahigh vacuum. Exploiting the break junction technique, we produced a 1G0 contact and broke it by applying a voltage ramp. The break voltage of each metal exhibits a broad distribution, and the average break voltage decreases as Au > Cu & Ag, in consistent with the elemental dependence of the high-bias stability of the 1G0 contact suggested in previous experimental studies. In AuAg alloys, the break-voltage distribution for some alloys exhibits a double-peak structure, each peak locating close to the break voltage of the 1G0 contact of pure Au and Ag, respectively. This observation suggests that the break voltage of AuAg alloys is locally determined by the elemental species of the atom occupying the contact site.

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“…We assume that the geometry of constrictions shown in Fig.1 catches limiting configurations of atomic contacts produced in the MCBJ experiments. To realize different contact atoms one could use dilute alloys as a wire material in the MCBJ, 19,20 or probe conductance through a single atom with an STM tip. 25 Since in the experiments the measurements are not performed for the equilibrium atomic configurations rather than the conductance is recorded dynamically under stretching of nanocontacts, 3 we did not optimize the interatomic distances and kept them the same as in bulk fcc metals Cu and Pd with lattice constants 6.83 a.u.…”

Section: Theoretical Approachmentioning

confidence: 99%

“…Systems of this type can be realized experimentally by using alloys to fabricate the point contacts. 19,20 According to our preliminary study, 21 we await the variation of conductance depending on the atomic number of the impurity situated at the central site. The number of conducting modes is also expected to change with respect to the atomic number of the impurity, especially because of the existence of the virtual bound states.…”

Section: Introductionmentioning

confidence: 99%

Ab initioapproach to the ballistic transport through single atoms

2006

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We present a systematic study of the ballistic electron conductance through sp and 3d transition metal atoms attached to copper and palladium crystalline electrodes. We employ the ab initio screened Korringa-Kohn-Rostoker Green's function method to calculate the electronic structure of nanocontacts while the ballistic transmission and conductance eigenchannels were obtained by means of the Kubo approach as formulated by Baranger and Stone. We demonstrate that the conductance of the systems is mainly determined by the electronic properties of the atom bridging the macroscopic leads. We classify the conducting eigenchannels according to the atomic orbitals of the contact atom and the irreducible representations of the symmetry point group of the system that leads to the microscopic understanding of the conductance. We show that if impurity resonances in the density of states of the contact atom appear at the Fermi energy, additional channels of appropriate symmetry could open. On the other hand the transmission of the existing channels could be blocked by impurity scattering.

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Current-induced transition in atomic-sized contacts of metallic alloys

Cited by 35 publications

References 20 publications

Stability of Atom-sized Metal Contacts under High Biases

Stability of Atom-sized Metal Contacts under High Biases

Break Voltage of the 1G0 Contact of Noble Metals and Alloys

Ab initioapproach to the ballistic transport through single atoms

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