Low-energy doublet states, quantum phase transition, and partial Kondo screening in the triple dot system

Kim, Chang-Il; Kang, Chol-Jin; Choe, Myong-Il; Yun, Chol-Song; Ahn, Jong-Kwan

doi:10.1016/j.ssc.2018.11.007

Cited by 6 publications

(2 citation statements)

References 27 publications

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“…[12] Moreover, quantum dot devices are particularly suitable for studying the Kondo effect owing to the strong operability. Especially the triple quantumdot system, which present various Kondo effects depending on magnetic field, [13,14] electron filling N tot , [15,16] quantum phase transition, [17][18][19] and low-energy electronic transport properties. [20][21][22][23][24][25][26][27][28] In a ring-like TTQD structure, spin chirality is induced by the noncoplanar spin configuration.…”

Section: Introductionmentioning

confidence: 99%

Chiral splitting of Kondo peak in triangular triple quantum dot

Liu¹,

Wang²,

Wei³

2022

Chinese Phys. B

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New characteristics of the Kondo effect, arising from spin chirality induced by the Berry phase in the equilibrium state, are investigated. The analysis is based on the hierarchical equations of motion (HEOM) approach in a triangular triple quantum-dot (TTQD) structure. In the absence of magnetic field, TTQD has four-fold degenerate chiral ground states with degenerate spin chirality. When a perpendicular magnetic field is applied, the chiral interaction is induced by the magnetic flux threading through TTQD and the four-fold degenerate states split into two chiral state pairs. The chiral excited states manifest as chiral splitting of the Kondo peak in the spectral function. The theoretical analysis is confirmed by the numerical computations. Furthermore, under a Zeeman magnetic field B, the chiral Kondo peak splits into four peaks, owing to the splitting of spin freedom. The influence of spin chirality on the Kondo effect signifies an important role of the phase factor. This work provides insight into the quantum transport of strongly correlated electronic systems.

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Section: Introductionmentioning

confidence: 99%

Chiral splitting of Kondo peak in triangular triple quantum dot

Liu¹,

Wang²,

Wei³

2022

Chinese Phys. B

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“…Non-magnetic Kondo trimers have been extensively examined theorecitally [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47], also in the case of fewchannel screening [48][49][50][51][52]. The presence of a QPT separating the conventional Kondo (CK) phase [53,54] from the exotic ferromagnetic Kondo (FK) regime hosting a non-screened local magnetic moment and singular dynamics at low temperatures [55,56] is well-established [37].…”

Section: Introductionmentioning

confidence: 99%

Magnetic Kondo regimes in a frustrated half-filled trimer

Wójcik,

Weymann,

Kroha

2020

Preprint

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We analyze theoretically the phase diagram of a triangular triple quantum dot with strong onsite repulsion coupled to ferromagnetic leads. This model includes the competition of magnetic ordering of local or itinerant magnetic moments, geometric frustration and Kondo screening. We identify all the phases resulting from this competition. We find that three Kondo phases -the conventional one, the two-stage underscreened one, and the one resulting from the ferromagnetic Kondo effect -can be realized at zero temperature, and all are very susceptible to the proximity of ferromagnetic leads. In particular, we find that the quantum dots are spin-polarized in each of these phases. Further, we discuss the fate of the phases at non-zero temperatures, where a plethora of competing energy scales gives rise to complex landscape of crossovers. Each Kondo regime splits into a pair of phases, one not magnetized and one comprising magnetically polarized quantum dots. We discuss our results in the context of heavy-fermion physics in frustrated Kondo lattices.

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Decoherence and maintenance of an entangled state in three-spin system coupled to ferromagnetic electrodes

Kim

Yun

et al. 2022

Physica B: Condensed Matter

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Low-energy doublet states, quantum phase transition, and partial Kondo screening in the triple dot system

Cited by 6 publications

References 27 publications

Chiral splitting of Kondo peak in triangular triple quantum dot

Chiral splitting of Kondo peak in triangular triple quantum dot

Magnetic Kondo regimes in a frustrated half-filled trimer

Decoherence and maintenance of an entangled state in three-spin system coupled to ferromagnetic electrodes

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