Thermally assisted Pauli spin blockade in double quantum dots

TL;DR

This paper explores how increasing temperature influences spin blockade phenomena in double quantum dots, revealing thermally induced effects that alter electron transport and spin states.

Contribution

It demonstrates the occurrence of thermally assisted Pauli spin blockade and its coexistence with Coulomb blockade, highlighting temperature's role in spin transport in quantum dots.

Findings

Thermal energy induces quadruplet Pauli spin blockade at higher temperatures.

Coexistence of Coulomb and Pauli spin blockades observed due to thermal effects.

Standard triplet Pauli spin blockade is gradually smeared out with increasing temperature.

Abstract

We investigate the influence of thermal energy on the current flow and electron spin states in double quantum dots in series. The quadruplet Pauli spin blockade, which is caused by the quadruplet and doublet states, occurs at low temperatures affecting the transport properties. As the temperature increases, the quadruplet Pauli spin blockade occurs as a result of the thermal energy, even in regions where it does not occur at low temperatures. This is because the triplet state is formed in one dot as a result of the gradual change of the Fermi distribution function of the electrodes with increasing temperature. Moreover, the thermally assisted Pauli spin blockade results in coexistence of the Coulomb and Pauli spin blockades. Conversely, for the standard triplet Pauli spin blockade, which occurs as a result of the triplet and singlet states, the current through the double dots monotonously smears out as the temperature increases. Therefore, the thermally assisted Pauli spin blockade is not clearly observed. However, the coexistence of the Coulomb and triplet Pauli spin blockades as a result of the thermal energy is clearly obtained in the calculation of the probability of the spin state in the double dots.