Abstract
The large spin–orbit coupling in the valence band of group IV semiconductors provides an electric field knob for spin-qubit manipulation. This fact can be exploited with acceptor based qubits. Spin manipulation of holes bound to acceptors in engineered SiGe quantum wells depends very strongly on the electric field applied and on the heterostructure parameters. The g-factor is enhanced by the Ge content and can be tuned by shifting the hole wave-function between the heterostructure constituent layers. The lack of inversion symmetry induced both by the quantum well and the electric fields together with the g-factor tunability allows the possibility of different qubit manipulation methods such as electron spin resonance, electric dipole spin resonance and g-tensor modulation resonance. Rabi frequencies up to hundreds of MHz can be achieved by electric field manipulation of heavy-hole qubits, and of the order of GHz with light-hole qubits.
Highlights
Solid state spin qubits such as electron spin in quantum dots [1], nuclear spin of a donor [2], electron spin in SiGe heterostructures [3] or singlet–triplet states of two electron spins [4] are promising candidates for the creation of a quantum computer with desirable properties like scalability or long coherence times
For heavy holes (HHs) qubits, we explore three different ways of manipulating the acceptors: electron spin resonance with magnetic fields (ESR), electric dipole spin resonance (EDSR) and g-tensor modulation resonance (g-TMR)
The effective dipole moment p is proportional to the probability density in the central cell region and decreases when x increases as the quantum well becomes more of germanium type and the hole wavefunction in Ge is more widespread than in Si
Summary
Solid state spin qubits such as electron spin in quantum dots [1], nuclear spin of a donor [2], electron spin in SiGe heterostructures [3] or singlet–triplet states of two electron spins [4] are promising candidates for the creation of a quantum computer with desirable properties like scalability or long coherence times. Most spin-qubits rely on the use of time dependent magnetic fields to perform operations, but experimentally it is quite difficult to localize a time dependent magnetic field on a single qubit. This makes desirable to look for ways to manipulate the qubit states only by electric fields, like electric dipole spin resonance (EDSR) [13, 14] or g-tensor modulation resonance (g-TMR) [15]
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