Reliability of the Heitler-London approach for the exchange coupling between electrons in semiconductor nanostructures

Abstract

We calculate the exchange coupling J between electrons in a double-well potential in a two-dimensional semiconductor environment within the Heitler-London (HL) approach. Two functional forms are considered for the double-well potential. We show that by choosing an appropriate and relatively simple single-electron variational wave function it is possible, within the HL approach, to significantly improve the estimates for J. In all cases the present scheme overcomes the artifacts and limitations at short interdot distances, previously attributed to the HL method, where unphysical triplet ground states have been found, and leads to an overall agreement with analytic interpolated expressions for J obtained for a donor-type model potential.

arXiv comment5 pages, 4 Postscript figures, to be published in Phys. Rev. B

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• Bounds to electron spin qubit variability for scalable CMOS architectures
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• Suppression of charge noise using barrier control of a singlet-triplet qubit
• Extended orbital modeling of spin qubits in double quantum dots
• Coupling of bonding and antibonding electron orbitals in double quantum dots by spin-orbit interaction
• Path integral simulation of exchange interactions in CMOS spin qubits
• Energy spectrum, exchange interaction and gate crosstalk in a pair of double-quantum-dot system: a molecular orbital calculation
• Ab initio modelling of quantum dot qubits: Coupling, gate dynamics and robustness versus charge noise
• On the validity of microscopic calculations of double-quantum-dot spin qubits based on Fock-Darwin states