Long-range overlapping of Kondo clouds in open triple quantum dots

Abstract

We study entanglement of Kondo clouds in an open triple quantum dots (OTQDs) system based on the dissipaton equation of motion (DEOM) theory. A comprehensive picture of the long-range entanglement of Kondo clouds is sketched by the spectral functions, spin-spin correlation and dot occupancies of OTQDs. We find that for the configuration (N1, N2, N3) = (1, 0, 1), a conduction electrons peak occurs in the spectral function of intermediate QD in Kondo regime. This peak resulting from the overlapping of the two Kondo clouds forming from between the two peripheral QDs and leads, enhances with decreasing temperature and increasing dot-lead coupling. Both the spin-spin correlations between the two adjacent QDs and the two peripheral QDs owns negative values. It also confirms the physical picuture of the overlapping between left and right Kondo clouds via the intermediate QD. Moreover, the transition of the effective electron occupation and the spectral function of intermediate QD in Kondo regime also indicates the entanglement of Kondo clouds enhancing with decreasing temperature and increasing dot-lead coupling. This investigation will be beneficial to detect the Kondo clouds and to further explore Kondo physics in related experiment setups.

Chiral splitting of Kondo peak in triangular triple quantum dot

“…[55] Recently, in open triple QDs, Cheng et al investigated the reappearance of the Kondo effect [45] and long-range overlapping of Kondo clouds. [48] Appendix B: Some supplementary information about the physical image…”

“…In recent years, HEOM has been widely used to investigate the Kondo effect and transport properties under equilibrium and non-equilibrium conditions in quantum dot systems. [33,[45][46][47][48]…”

“…As a successful application, the HEOM approach has been proved to be capable of quantitatively describing the essential signatures of Kondo physics [33,39,46,48] and achieving the accuracy of the NRG approach. Currently for a typical Anderson model, the HEOM approach reaches quantitatively accuracy for temperature T ≥ 0.1T K (Kondo temperature).…”

Capacitive coupling induced Kondo–Fano interference in side-coupled double quantum dots*

“…[56] Finally, in open triple QDs, Cheng et al investigated the reappearance of the Kondo effect and long-range overlapping of Kondo clouds via the HEOM approach. [57,58] pole term, the numerator indicates the weight of an elementary excitation, while the denominator denotes its position. This means the six substates are at ω =𝜖 d , 𝜖 d + U, 𝜖 d + U 12 , 𝜖 d +U 12 +U, 𝜖 d + 2U 12 , and 𝜖 d + 2U 12 +U.…”

Spin and charge Kondo effects in capacitively coupled double quantum dots

“…As a non-perturbative method, the HEOM approach is capable of quantitatively describing the essential signatures of Kondo physics and achieving the accuracy of the numerical renormalization group (NRG) approach [29,[36][37][38][39][40][41]. The main limitation lies in the numerical difficulty at near-zero temperature (T < 0.1T K ) and for large degree of the system.…”