Spectral properties and quantum phase transitions in parallel triple quantum dots

Wang, Weizhong

doi:10.1103/physrevb.76.115114

Cited by 39 publications

(25 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the U-dominated regime, the interplay between U and t in triple dot structures has been well elucidated. [19,34] Therefore, in order to make a clear understanding of the interplay between V and t, and compare with previous works, we fix U = 0.1, V = 0.15, and Γ = 0.01 throughout this paper. Note that we have assumed V > U here, which means that the three spatially separated quantum dots are not too small, and may have the stronger capacitance couplings to each other.…”

Section: Resultsmentioning

confidence: 99%

“…Under this transformation, only the bonding state hybridizes with the conduction band, while the antibonding states seem like quasi-localized states. [34,35,45,53] Therefore, the parallel triangular TQD system is completely equivalent to the model shown in Fig. 3(b).…”

Section: Resultsmentioning

confidence: 99%

“…[31] For a parallel TQD system with one central dot and two side dots, the ferromagnetic Kondo effect is studied, [32] and the spin correlation between two side dots can be ferromagnetic or antiferromagnetic, depending on the charge of the central dot. [33] When three dots are coupled symmetrically to two leads, there exist two first-order QPTs due to the competition between the interdot tunnel coupling and the Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange interaction, [34] and the conductance is discontinuous through the quantum phase transitions. [35] For a triangular TQD with only one dot connected to the leads, the QPT and Kondo effect are studied in impurity trimers.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quantum phase transition and Coulomb blockade effect in triangular quantum dots with interdot capacitive and tunnel couplings

et al. 2015

Self Cite

View full text Add to dashboard Cite

The quantum phase transition and the electronic transport in a triangular quantum dot system are investigated using the numerical renormalization group method. We concentrate on the interplay between the interdot capacitive coupling V and the interdot tunnel coupling t. For small t, three dots form a local spin doublet. As t increases, due to the competition between V and t, there exist two first-order transitions with phase sequence spin-doublet-magnetic frustration phase-orbital spin singlet. When t is absent, the evolutions of the total charge on the dots and the linear conductance are of the typical Coulomb-blockade features with increasing gate voltage. While for sufficient t, the antiferromagnetic spin correlation between dots is enhanced, and the conductance is strongly suppressed for the bonding state is almost doubly occupied.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quantum phase transition and Coulomb blockade effect in triangular quantum dots with interdot capacitive and tunnel couplings

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…16,21 The competition between the Kondo coupling and interdot hopping leads to a local triplet-singlet QPT. 22 In DQD systems separately coupled to two leads and subject to an interdot antiferromagnetic spin-spin interaction, this local triplet-singlet transition has also been observed. 20 In models of interacting magnetic impurities coupled to a metallic host, the local triplet-singlet QPT is of the first order for symmetric Kondo coupling and is of the Kosterlitz-Thouless (KT) type for asymmetric Kondo coupling.…”

Section: Introductionmentioning

confidence: 89%

Kondo effect and continuous quantum phase transitions in double quantum dots with on-site and interdot repulsion and magnetic field

Wang

2011

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

By means of the numerical renormalization group method, I study the Kondo effect and quantum phase transitions in a double quantum dot system with on-site repulsion U , interdot repulsion V , and magnetic field B. At zero temperature and B = 0, there is a local spin triplet-singlet transition of the Kosterlitz-Thouless type when V increases to a critical value V c ≈ U . With increasing B, a singlet-triplet transition of the second order occurs at a critical magnetic field B c ≈ V − U . The magnetic susceptibility and the first derivatives of the spin correlation and double occupation are expected to diverge at B c and to have different critical exponents, which are universal for different parameters. An appropriate magnetic field can restore the Kondo effect.

show abstract

“…[17,18] While in the theoretical field, TQD structure offers the potential to study some new fascinating phenomena at low temperatures, including the Kondo effect, [19][20][21][22] the Fermi liquid theory, [23,24] the quantum interference, [25,26] and various kinds of quantum phase transitions (QPT). [27][28][29][30][31] TQD structure could be organized in serial, [32,33] parallel, [34][35][36] or triangular [37][38][39][40] spatial configuration, which may naturally result in different quantum behaviors. Among these configurations, the parallel TQD (PTQD) system is a basic one, which has also inspired a wealth of research.…”

Section: Introductionmentioning

confidence: 99%

Phase transition and charge transport through a triple dot device beyond the Kondo regime

Xiong¹,

Zhu²,

He³

2018

Chinese Phys. B

View full text Add to dashboard Cite

Semiconductor quantum dot structure provides a promising basis for quantum information processing, within which to reveal the quantum phase and charge transport is one of the most important issues. In this paper, by means of the numerical renormalization group technique, we study the quantum phase transition and the charge transport for a parallel triple dot device in the strongly correlated limit, focusing on the effect of inter-dot hopping t beyond the Kondo regime. We find the quantum behaviors depend closely on the initial electron number on the dots, and the present model may map to single, double, and side-coupled impurity models in different parameter spaces. An orbital spin-1/2 Kondo effect between the conduction leads and the bonding orbital, and several magnetic-frustration phases are demonstrated when t is adjusted to different regimes. To understand these phenomena, a canonical transformation of the energy levels is given, and important physical quantities with respect to increasing t and necessary theoretical discussions are shown.

show abstract

Spectral properties and quantum phase transitions in parallel triple quantum dots

Cited by 39 publications

References 50 publications

Quantum phase transition and Coulomb blockade effect in triangular quantum dots with interdot capacitive and tunnel couplings

Quantum phase transition and Coulomb blockade effect in triangular quantum dots with interdot capacitive and tunnel couplings

Kondo effect and continuous quantum phase transitions in double quantum dots with on-site and interdot repulsion and magnetic field

Phase transition and charge transport through a triple dot device beyond the Kondo regime

Contact Info

Product

Resources

About