Tuning the electrically evaluated electron Landé<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>g</mml:mi></mml:math>factor in GaAs quantum dots and quantum wells of different well widths

Allison, Giles; Fujita, Takafumi; Morimoto, Keiko; Teraoka, S.; Larsson, Marcus; Kiyama, H.; Oiwa, A.; Haffouz, S.; Austing, D. G.; Ludwig, Arne; Wieck, A. D.; Tarucha, Seigo

doi:10.1103/physrevb.90.235310

Cited by 14 publications

(17 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A perturbative treatment of field-induced changes in the effective densities of states for electrons with different components of the total angular momentum allows the scaling to be interpreted in terms of an effective spin-splitting of the impurity level by an energy proportional to Γǫ Z /D. A similar picture should hold for any realization of the Anderson impurity model with g i = 0, as seems likely to be achievable in lateral quantum dots [27].…”

Section: Introductionmentioning

confidence: 95%

See 1 more Smart Citation

Influence of Rashba spin-orbit coupling on the Kondo effect

et al. 2016

View full text Add to dashboard Cite

An Anderson model for a magnetic impurity in a two-dimensional electron gas with bulk Rashba spin-orbit interaction is solved using the numerical renormalization group under two different experimental scenarios. For a fixed Fermi energy, the Kondo temperature TK varies weakly with Rashba coupling α, as reported previously. If instead the band filling is low and held constant, increasing α can drive the system into a helical regime with exponential enhancement of TK . Under either scenario, thermodynamic properties at low temperatures T exhibit the same dependences on T /TK as are found for α = 0. Unlike the conventional Kondo effect, however, the impurity exhibits static spin correlations with conduction electrons of nonzero orbital angular momentum about the impurity site. We also consider a magnetic field that Zeeman splits the conduction band but not the impurity level, an effective picture that arises under a proposed route to access the helical regime in a driven system. The impurity contribution to the system's ground-state angular momentum is found to be a universal function of the ratio of the Zeeman energy to a temperature scale that is not TK (as would be the case in a magnetic field that couples directly to the impurity spin), but rather is proportional to TK divided by the impurity hybridization width. This universal scaling is explained via a perturbative treatment of field-induced changes in the electronic density of states.

show abstract

Section: Introductionmentioning

confidence: 95%

“…(27). After further transformation to an energy representation, the problem maps to a generalized two-channel Anderson model…”

Section: Model With Bulk Zeeman Fieldmentioning

confidence: 99%

Influence of Rashba spin-orbit coupling on the Kondo effect

et al. 2016

View full text Add to dashboard Cite

show abstract

“…In GaAs, the bulk g factor for electron carriers is g G = −0.44. In addition, the g factor in nanostructures is affected by details of electron confinement [8][9][10][11][12]. Deviations from the bulk GaAs g factor have been observed in various heterostructures and quantum-dot configurations, including dot-to-dot variations in quantum-dot arrays [6,7,[12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear and dot-dependent Zeeman splitting in GaAs/AlGaAs quantum dot arrays

et al. 2018

Self Cite

View full text Add to dashboard Cite

We study the Zeeman splitting in lateral quantum dots that are defined in GaAs-AlGaAs heterostructures by means of split gates. We demonstrate a nonlinear dependence of the splitting on magnetic field and its substantial variations from dot to dot and from heterostructure to heterostructure. These phenomena are important in the context of information processing since the tunability and dot-dependence of the Zeeman splitting allow for a selective manipulation of spins. We show that spin-orbit effects related to the GaAs band structure quantitatively explain the observed magnitude of the nonlinear dependence of the Zeeman splitting. Furthermore, spin-orbit effects result in a dependence of the Zeeman splitting on predominantly the out-of-plane quantum dot confinement energy. We also show that the variations of the confinement energy due to charge disorder in the heterostructure may explain the dependence of Zeeman splitting on the dot position. This position may be varied by changing the gate voltages, which leads to an electrically tunable Zeeman splitting.

show abstract

“…In search for generic features, we measured for various sample cooldowns, which can change the shape of the dot, and for both in-plane and perpendicular magnetic fields, by which we isolate the strong orbital effects of the latter. Due to the influence of the AlGaAs barriers [2], the g-factor is small, |g ⊥ | < 0.12 for an out-of-plane magnetic field, and, as we find from the analysis below, about five times smaller for in-plane fields. (These small values make it easier to analyze the behavior of the rates at small Zeeman energies, which are pushed to higher magnetic fields by the small g-factors.)…”

mentioning

confidence: 77%

“…We explain this behavior as due to the crossover of the dominant blockade lifting mechanism from the hyperfine to spin-orbit interactions and due to a change in the contribution of the charge decoherence. Electron spins in semiconductor quantum dots are promising resources for quantum information processing [1,2]. Laterally gated dots [5] are especially attractive due to the flexibility and scalability [4] of their design, and the possibility to electrically initialize [5], manipulate [6,7], and measure [8,9] the slowly relaxing [10,11] spin states.…”

mentioning

confidence: 99%

Signatures of Hyperfine, Spin-Orbit, and Decoherence Effects in a Pauli Spin Blockade

et al. 2016

Self Cite

View full text Add to dashboard Cite

We detect in real time inter-dot tunneling events in a weakly coupled two electron double quantum dot in GaAs. At finite magnetic fields, we observe two characteristic tunneling times, T d and T b , belonging to, respectively, a direct and a blocked (spin-flip-assisted) tunneling. The latter corresponds to lifting of a Pauli spin blockade and the tunneling times ratio η = T b /T d characterizes the blockade efficiency. We find pronounced changes in the behavior of η upon increasing the magnetic field, with η increasing, saturating and increasing again. We explain this behavior as due to the crossover of the dominant blockade lifting mechanism from the hyperfine to spin-orbit interactions and due to a change in the contribution of the charge decoherence.PACS numbers: 73.63. Kv, 73.23.Hk, 85.35.Gv, 76.60.Es Electron spins in semiconductor quantum dots are promising resources for quantum information processing [1,2]. Laterally gated dots [5] are especially attractive due to the flexibility and scalability [4] of their design, and the possibility to electrically initialize [5], manipulate [6,7], and measure [8, 9] the slowly relaxing [10,11] spin states. Pauli spin blockade (PSB) [12] plays a crucial role in electrical manipulations. PSB is established when the conservation of spin blocks a transition from an excited state, where two electrons in two dots have parallel spins, to the ground state, where they form a singlet in one dot. The spin can thus be detected by a local charge sensor as the presence or absence of a charge transition [13,14]. The blockade is lifted by spin flips, limiting the readout fidelities [15,16], as well as manipulations and preparations of quantum states. [17,18] In GaAs quantum dots, there are two important sources of electron spin flips: the spin-orbit coupling, and the hyperfine interaction with spins of atomic nuclei. Respectively, they dominate the spin relaxation time T 1 [19,20] and decoherence time T 2 [21-23]. Apart from causing detrimental effects, both of these can be utilized in quantum state manipulation as a means of coupling of the electrical control fields to spins [24][25][26][27]. It is known that the relative importance of these two effects changes with magnetic field strength and orientation [18,28,29]. By resolving the direct and spin-flip-assisted inter-dot tunneling, here we investigate experimentally the limit these factors impose on the effectiveness of PSB. We find a crossover in their dominance upon changing the magnetic field strength, which is fully consistent with our theory. Our results give guidance on how to increase the PSB effectiveness with importance for spin readout applications.Our device is a gate defined lateral double quantum dot (DQD), Fig. 1(a), weakly tunnel-coupled and isolated from reservoirs, with lead-dot tunneling rates of order Hz, and the inter-dot tunneling rate of order kHz. In this regime, where tunnel coupling energies are much smaller than orbital or charging energies, the two electron configurations span a basis of five states [...

show abstract

Tuning the electrically evaluated electron Landégfactor in GaAs quantum dots and quantum wells of different well widths

Cited by 14 publications

References 28 publications

Influence of Rashba spin-orbit coupling on the Kondo effect

Influence of Rashba spin-orbit coupling on the Kondo effect

Nonlinear and dot-dependent Zeeman splitting in GaAs/AlGaAs quantum dot arrays

Signatures of Hyperfine, Spin-Orbit, and Decoherence Effects in a Pauli Spin Blockade

Contact Info

Product

Resources

About