Thermoelectric voltage switching in gold atomic wire junctions

Abstract

We explore the thermoelectric properties of gold atomic chains bridging gold electrodes by means of ab initio and semi-empirical calculations, and heuristic reasoning. We predict the thermoelectric voltage induced by a temperature difference across such junctions to oscillate, repeatedly changing sign, as a function of the number of atoms N making up the atomic chain. We also predict the amplitude of the oscillations to be proportional to N for long atomic chains. Further we predict the thermoelectric voltage to change sign, in some cases, if the junction is stretched without changing N . Our predictions apply regardless of whether regular or irregular electrode grain boundaries are present and whether the electrodes are symmetric or asymmetric. Our findings may pave the way to the realization of new mechanically controllable voltage switches enabling direct conversion of heat into electricity in energy harvesting applications.

Nanoscale Organic Thermoelectric Materials: Measurement, Theoretical Models, and Optimization Strategies

“…Clearly, the conductance and Seebeck coefficient of molecular lines are closely related to the number of benzene rings in a chain structure composed of several identical units while the magnitude and sign of Seebeck can simultaneous change by alternate the anchoring group. Similarly, theoretical simulation also predict the interesting sign oscillation phenomenon of Seebeck coefficient when length of the molecule chain is increasing . It means that the transformation of thermoelectric devices from n‐type to p‐type can be easily realized by control the length of the molecular chain.…”

“…Similarly, theoretical simulation also predict the interesting sign oscillation phenomenon of Seebeck coefficient when length of the molecule chain is increasing. [155,156] It means that the transformation of thermoelectric devices from n-type to p-type can be easily realized by control the length of the molecular chain. The more direct evidence for size effect on thermoelectric performance regulation is the ZT value (electron contribution) can also increase with the number of benzene rings, [157] which usually indicates the enhancement of power factor (see Figure 10d).…”

Mechanisms of jump to contact and conductance plateau formation in copper atomic junctions in vacuum and aqueous environments

“…To do this, each one of the valence orbitals 4s, 4p x , 4p y , 4p z , 3d xy , 3d xz , 3d yz , 3d z 2 , and 3d x 2 −y 2 belonging to the ten (seven) farthest atoms of each electrode from the junction is connected to a onedimensional ideal lead representing electron reservoirs (see Figs. 1(a)-(d)) [8,[48][49][50][51][52]. The electron transmission amplitudes t ji (E) through the system consisting of the electrodes and water molecules are obtained by solving the Lippmann-Schwinger equation…”

“…Metallic junctions and the process of their contact formation have been the subject of many experimental and theoretical studies exploring physical properties, such as electrical conduction [1][2][3][4], quantum interference [5][6][7] and thermoelectric energy conversion [7][8][9][10] at the atomic and molecular scales. Achieving control over the electronic transport properties of single atom contacts is crucial for the realization of practical nanoelectronic devices.…”

Kondo cooling in quantum impurity systems

“…In the past decade, Peltier cooling in nanoscopic systems has attracted enormous theoretical [9][10][11][12][13][14][15][16][17][18] and experimental [19][20][21][22][23][24][25][26][27][28] efforts. Thanks to the impressive advances in the synthesis, fabrication and manipulation of nano-sized materials, Peltier cooling has been realized in molecular junctions [19-21, 27, 28], organic thermoelectric flakes [22,26], and ferromagnetic/ferrimagnetic metal films [23][24][25].…”