Controlling Fano and Dicke effects via a magnetic flux in a two-site Anderson model

Abstract

The electronic transport through a parallel double quantum-dot molecule attached asymmetrically to leads is studied under a magnetic field. We model the system by means of a non interacting twoimpurity Anderson Hamiltonian. We find that the conductance shows Fano and Dicke effects that can be controlled by the magnetic flux.

Electronic transport through a parallel-coupled triple quantum dot molecule: Fano resonances and bound states in the continuum

“…17,20 Notice that bound states in the continuum occur for numerous combinations of dot-lead couplings and Aharonov-Bohm phases, but, for simplicity, we will restrict our attention to the particular cases:…”

Quantum transport of electrons through a parallel-coupled triple quantum-dot molecule

“…This resonance is associated to a long-lived molecular state, where the lifetime is controlled by the magnetic field. For specific values of the magnetic flux, this molecular state becomes totally uncoupled from the leads [3,6], and a "bound state in the continuum" (BIC) is formed. This state immersed in a continuum is the result of the interference of resonances belonging to different channels.…”

“…On the other hand, we can see of Eq. (16) that if V 1 = V 3 and V 2 = √ 2V 1 , two BIC's are simultaneously formed when φ = 4nπ: one in the state 2 (ε = ε 0 ), and other either in state 1 (ε = ε 0 − √ 2t) or 3 (ε = ε 0 + √ 2t), depending on the parity of n. In a parallel double quantum dot molecule, a seemingly simpler condition gives rise to one BIC, which is formed whenever φ is a even multiple of π (that is, Φ = nΦ 0 , n integer) [3,6]. Notice that BICs occur for an infinite number of combinations of dot-lead couplings and Aharonov-Bohm phases, but for simplicity in what follows we focus in the case in that V 1 = V 3 ≡ V and V 2 = √ 2V .…”

“…For this reason, multiple connected geometries involving quantum dots exhibit quantum interference effects. Several works have been concerned with the study of transmission through a double quantum dot molecule embedded in an AharonovBohm interferometer [1][2][3][4][5]. This system is characterized by the formation of a tunable Fano resonance in the conductance spectrum.…”

Quantum electron splitter based on two quantum dots attached to leads

“…In this regard, it has recently been demonstrated that coupled QDs shows the electronic counterpart of Fano and Dicke effects that can be controlled via a magnetic flux. 1 In the case of QDs, Fano resonance coexists with Coulomb interaction, giving rise to new quantum transport regimes. 2 In addition, Fano resonances have been clearly observed in a quantum wire ͑QW͒ with a sidecoupled QD, and it has been proven that this geometry can be used as an accurate interferometer.…”