SiGe/Si quantum dot electron spin decoherence dependence on ${}^{73}$Ge

Abstract

We theoretically study the nuclear spin induced decoherence of a quantum dot in Si that is confined at a SiGe interface. We calculate decoherence time dependence on ${}^{73}$Ge in the barrier layer to evaluate the importance of Ge as well as Si enrichment for long decoherence times. We use atomistic tight-binding modeling for an accurate account of the electron wavefunction which is particularly important for determining the contact hyperfine interactions with the Ge nuclear spins. We find decoherence times due to Ge spins at natural concentrations to be milliseconds. This suggests SiGe/Si quantum dot devices employing enriched Si will require enriched Ge as well in order to benefit from long coherence times. We provide a comparison of $T_2$ times for various fractions of nonzero spin isotopes of Si and Ge.

References in corpus (9)

• Electron spin coherence exceeding seconds in high purity silicon
• Theory of electron spin decoherence by interacting nuclear spins in a quantum dot
• Electron spin decoherence in isotope-enriched silicon
• Physical mechanisms of interface-mediated intervalley coupling in Si
• Pauli spin blockade in undoped Si/SiGe two-electron double quantum dots
• Tunable singlet-triplet splitting in a few-electron Si/SiGe quantum dot
• Decoherence induced by anisotropic hyperfine interaction in Si spin qubits
• Enhancement-mode buried strained silicon channel quantum dot with tunable lateral geometry
• Effects of Interface Disorder on Valley Splitting in SiGe/Si/SiGe Quantum Wells

Cited by in corpus (8)

• Quantum many-body theory for electron spin decoherence in nanoscale nuclear spin baths
• Low-frequency spin qubit detuning noise in highly purified ${}^{28}$Si/SiGe
• Probing low noise at the MOS interface with a spin-orbit qubit
• Quantum Decoherence of the Central Spin in a Sparse System of Dipolar Coupled Spins
• A silicon singlet-triplet qubit driven by spin-valley coupling
• Valley splittings in Si/SiGe quantum dots with a germanium spike in the silicon well
• Electron spin coherence of shallow donors in natural and isotopically enriched germanium
• Magnetic Gradient Fluctuations from Quadrupolar ${}^{73}$Ge in Si/SiGe Exchange-Only Qubits