Guangyu Yi's research while affiliated with Northeastern University and other places

... A Y-shaped junction device consisting of two metallic leads, each connected to a SC electrode through two QDs, played the role of a Cooper-pair splitter and allowed control over CAR and LAR processes when tuning the gate voltages [77]. The Andreev transport properties of double-QD Cooper-pair splitters [78][79][80][81] or multi-QD-MBS setups [82][83][84][85][86][87][88][89] have also been theoretically explored. In addition, the thermoelectric properties in Cooper-pair splitters with QDs have been explored both theoretically [90][91][92] and experimentally with graphene-based QDs [93]. ...

... [31] Furthermore, persistent currents are sensitive to external perturbations, any change that makes variations in the spectra of a determinated system will be observed in the persistent current. In this sense, the use of persistent currents with the purpose of detecting MBSs has been studied theoretically by Gong et al., [32] where a TSC is embedded in the QD-ring. As a result, the relevant signature of the MBSs is the cancellation of persistent current signal when the ring parity is even. ...

... Using the finite-difference method, the electric and magnetic field effects on the on-center and off-center impurity binding energy in CQD have been studied by Wang et al. 48 . In that work, the electric (magnetic) field has been considered perpendicular (parallel) to the axial axis of the structure. ...

... For instance, in a T-shaped double-QD junction, an unusual transition occurs in the half-filled case, different from the serially coupled geometry [10][11][12]. In the Fano-Josephson junction, an intermediate bistable phase has been found to appear in the phase-transition process [13]. ...

... Only a limited number of studies have been done also on the non-equilibrium effects in the QQD systems and mainly focused on the effects of the spinpolarization, magnification and circulation of the persistent current [34,35], as well the current oscillation phenomena. The current-voltage (J −V ) characteristics have been investigated in some particular cases [28,33,36], including a possibility of negative differential conductance (NDC) effects [33], analogous to those previously found for parallel quantum dots [12,[37][38][39][40]. ...

... The quantum dot thus can possess BCS-like states in contrast to their original discrete states 10 that are under a more direct influence of the Coulomb blockade. Furthermore, one of the most important effects of the SC-QD coupling is the emergence of Andreev bound states (ABS) [11][12][13] found in SC-QD heterostructures which carry important information on phase transitions for the dot. ...

... A Y-shaped junction device consisting of two metallic leads, each connected to a SC electrode through two QDs, played the role of a Cooper-pair splitter and allowed control over CAR and LAR processes when tuning the gate voltages [77]. The Andreev transport properties of double-QD Cooper-pair splitters [78][79][80][81] or multi-QD-MBS setups [82][83][84][85][86][87][88][89] have also been theoretically explored. In addition, the thermoelectric properties in Cooper-pair splitters with QDs have been explored both theoretically [90][91][92] and experimentally with graphene-based QDs [93]. ...

... Thus, a tightly confined principal direction implies a reduced polarizability element. Similarly, highly symmetric cross sections such as circles [21], hexagons and squares [22] lead to isotropic polarizability tensors. It follows that angle-resolved low-field Stark spectroscopy provides useful geometric information about symmetries and nanowire aspect ratio. ...

... The present work is devoted to an exact study of the mixed spin-(1/2, 1) Ising chain model, which accounts both for the axial zero-field splitting (AZFS) as well as the rhombic zero-field splitting (RZFS) parameter in a presence of the applied longitudinal magnetic field. It is worthy of notice that the special limiting case of this model system in an absence of the external magnetic field has been proposed and exactly solved by Wu et al. [4,5,6] using the rigorous procedure based on the Jordan-Wigner transformation [7] (see Refs. [8,9,10] for related works on this subject). However, it has been recently shown by the present authors [11] that the exact results obtained by Wu et al. [4,5] can also be recovered by another independent way by making use of the transfer-matrix method. ...

... Also, for this S = 1 model, the phase diagram at finite temperatures has been studied by using analytical and numerical techniques, such as the standard mean-field approximation [17][18][19], standard effective-field theory [20,21], improved pair approximation [22], effectivefield theory with correlations [23], and an effective correlated mean-field scheme [24]. Even mixed spin-1/2 and 1 [25,26] and mixed spin-1/2 and 3/2 [27] have also been studied in the literature. This means that reasonable knowledge of the main transition properties of the S = 1 system has been achieved, at least in a qualitative aspect. ...