Thermopower of a single-electron transistor in the regime of strong inelastic cotunneling

Abstract

We study Coulomb blockade oscillations of thermoelectric coefficients of a single electron transistor based on a quantum dot strongly coupled to one of the leads by a quantum point contact. At temperatures below the charging energy EC the transport of electrons is dominated by strong inelastic cotunneling. In this regime we find analytic expressions for the thermopower as a function of temperature T and the reflection amplitude r in the contact. In the case when the electron spins are polarized by a strong external magnetic field, the thermopower shows sinusoidal oscillations as a function of the gate voltage with the amplitude of the order of e −1 |r|. We obtain qualitatively different results in the absence of the magnetic field. At temperatures between EC and EC|r| 2 the thermopower oscillations are sinusoidal with the amplitude of order e −1 |r| 2 ln. On the other hand, at T ≪ EC|r| 2 we find non-sinusoidal oscillations of the thermopower with the amplitude ∼ e −1 |r| T /EC ln(EC/T ).

Thermopower of a superconducting single-electron transistor

“…1 Recently, thermoelectric effects in single-electron devices such as the thermopower have attracted growing interest. [2][3][4][5][6][7][8][9][10][11] The thermopower is related to the current that arises due to a finite temperature difference between the two leads.…”

“…4,5 Recently, the thermopower of open quantum dots with strong coupling to the leads was investigated. [6][7][8] Further, the influence of Kondo correlations in ultrasmall quantum dots on the thermoelectric effects was studied in Refs. 9 and 10, while the thermopower of a molecule with internal degrees of freedom and weakly coupled to the leads was discussed in Ref.…”

Thermopower signatures and spectroscopy of the canyon of conductance suppression

“…The thermopower of the usual Coulomb blockade sequential tunneling peaks and the cotunneling signal were addressed in Refs. [44][45][46][47][48][49][50][51][52].…”

Universality and quantization of the power-to-heat ratio in nanogranular systems

“…(1) is a result of inelastic cotunneling processes, which govern the electron transport. The essence of these processes is that an electron tunnels via virtual states in intermediate grains thus bypassing the huge Coulomb barrier [2,4,[6][7][8][9][10][11][12][13][14][15][16][17][18]. This can be visualized as coherent superposition of two events: tunneling of an electron into a granule and the simultaneous escape of another electron from the same granule.…”