Spin-orbit coupling mediated tunable electron heat capacity of quantum wells

TL;DR

This paper demonstrates that the electron heat capacity in quantum wells can be tuned using spin-orbit coupling parameters, strain, and well dimensions, with implications for spintronics and thermodynamics.

Contribution

It introduces a method to control electron heat capacity via Rashba and Dresselhaus spin-orbit interactions in quantum wells, and proposes a way to estimate spin lifetimes from thermodynamic measurements.

Findings

Heat capacity is higher for spin-down electrons.

Wider wells reduce the heat capacity.

Uniaxial strain further lowers the heat capacity.

Abstract

The heat capacity of conduction electrons obtained from the Sommerfeld expansion is shown to be tunable via the Rashba and Dresselhaus spin-orbit coupling parameters. Using an AlInSb/InSb/AlInSb as a representative heterostructure with alterable well and asymmetric barrier regions, the heat capacity is found to be higher for the spin-down electrons and suffers a reduction for wider wells. A further lowering is obtained through the application of an uniaxial strain. Finally, we suggest a method to determine the spin lifetimes for spins relaxing via the D'yakonov-Perel' mechanism from experimental estimates of thermodynamic potentials such as the Helmholtz free energy and the heat capacity.