scholarly journals Interplay between Coulomb blockade and Josephson effect in a topological superconductor–quantum dot device

2016 ◽  
Vol 93 (18) ◽  
Author(s):  
Yu-Li Lee ◽  
Yu-Wen Lee
Keyword(s):  
Quantum Dot ◽  
Coulomb Blockade ◽  
Josephson Effect ◽  
Topological Superconductor

scholarly journals Topological isoconductance signatures in Majorana nanowires

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. S. Ricco ◽  
J. E. Sanches ◽  
Y. Marques ◽  
M. de Souza ◽  
M. S. Figueira ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Transport Properties ◽  
Spin Polarization ◽  
Bound States ◽  
Spin Asymmetry ◽  
Experimental Protocol ◽  
Zero Bias ◽  
Topological Superconductor ◽  
Hybrid Device ◽  
Majorana Bound States

AbstractWe consider transport properties of a hybrid device composed by a quantum dot placed between normal and superconducting reservoirs, and coupled to a Majorana nanowire: a topological superconducting segment hosting Majorana bound states (MBSs) at the opposite ends. It is demonstrated that if highly nonlocal and nonoverlapping MBSs are formed in the system, the zero-bias Andreev conductance through the dot exhibits characteristic isoconductance profiles with the shape depending on the spin asymmetry of the coupling between the dot and the topological superconductor. Otherwise, for overlapping MBSs with less degree of nonlocality, the conductance is insensitive to the spin polarization and the isoconductance signatures disappear. This allows to propose an alternative experimental protocol for probing the nonlocality of the MBSs in Majorana nanowires.

KONDO EFFECT AND SPIN-CHARGE SEPARATION IN QUANTUM DOTS

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1426-1442
Author(s):  
L. I. GLAZMAN ◽  
F. W. J. HEKKING ◽  
A. I. LARKIN
Keyword(s):  
Quantum Dot ◽  
Charge Separation ◽  
Coulomb Blockade ◽  
Kondo Effect ◽  
Broad Band ◽  
Single Mode ◽  
Kondo Temperature ◽  
Average Charge ◽  
Opposite Case ◽  
Anderson Impurity Model

The Kondo effect in a quantum dot is discussed. In the standard Coulomb blockade setting, tunneling between the dot and the leads is weak, the number of electrons in the dot is well-defined and discrete; the Kondo effect may be considered in the framework of the conventional one-level Anderson impurity model. It turns out however, that the Kondo temperature TK in the case of weak tunneling is extremely low. In the opposite case of almost reflectionless single-mode junctions connecting the dot to the leads, the average charge of the dot is not discrete. Surprisingly, its spin may remain quantized: s=1/2 or s=0, depending (periodically) on the gate voltage. Such a "spin-charge separation" occurs because, unlike an Anderson impurity, a quantum dot carries a broad-band, dense spectrum of discrete levels. In the doublet state, the Kondo effect develops with a significantly enhanced TK. Like in the weak-tunneling regime, the enhanced TK exhibits strong mesoscopic fluctuations. The statistics of the fluctuations is universal, and related to the Porter-Thomas statistics of the wave function fluctuations.

scholarly journals Josephson effect in junctions of conventional and topological superconductors

2018 ◽  
Vol 9 ◽  
pp. 1659-1676 ◽  
Author(s):  
Alex Zazunov ◽  
Albert Iks ◽  
Miguel Alvarado ◽  
Alfredo Levy Yeyati ◽  
Reinhold Egger
Keyword(s):  
Bound States ◽  
Josephson Effect ◽  
Mean Field ◽  
Josephson Current ◽  
Field Analysis ◽  
Current Phase ◽  
Topological Superconductor ◽  
Topological Superconductors ◽  
Spin Singlet ◽  
Hybrid Devices

We present a theoretical analysis of the equilibrium Josephson current-phase relation in hybrid devices made of conventional s-wave spin-singlet superconductors (S) and topological superconductor (TS) wires featuring Majorana end states. Using Green’s function techniques, the topological superconductor is alternatively described by the low-energy continuum limit of a Kitaev chain or by a more microscopic spinful nanowire model. We show that for the simplest S–TS tunnel junction, only the s-wave pairing correlations in a spinful TS nanowire model can generate a Josephson effect. The critical current is much smaller in the topological regime and exhibits a kink-like dependence on the Zeeman field along the wire. When a correlated quantum dot (QD) in the magnetic regime is present in the junction region, however, the Josephson current becomes finite also in the deep topological phase as shown for the cotunneling regime and by a mean-field analysis. Remarkably, we find that the S–QD–TS setup can support φ0-junction behavior, where a finite supercurrent flows at vanishing phase difference. Finally, we also address a multi-terminal S–TS–S geometry, where the TS wire acts as tunable parity switch on the Andreev bound states in a superconducting atomic contact.

Microwave modulation of Coulomb-blockade oscillations in a quantum dot

1996 ◽  
Vol 227 (1-4) ◽  
pp. 98-101 ◽  
Author(s):  
K. Fujii ◽  
W. Gödel ◽  
D.A. Wharam ◽  
S. Manus ◽  
J.P. Kotthaus ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Coulomb Blockade ◽  
Microwave Modulation

Investigation of an open quantum dot with a Coulomb blockade quantum dot detector

2002 ◽  
Vol 12 (1-4) ◽  
pp. 827-829
Author(s):  
S.J. Geer ◽  
A.G. Davies ◽  
C.G. Smith ◽  
L.D. Macks ◽  
W.R. Tribe ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Coulomb Blockade ◽  
Open Quantum

scholarly journals Statistics of the Coulomb-blockade peak spacings of a silicon quantum dot

1999 ◽  
Vol 59 (16) ◽  
pp. R10441-R10444 ◽  
Author(s):  
F. Simmel ◽  
David Abusch-Magder ◽  
D. A. Wharam ◽  
M. A. Kastner ◽  
J. P. Kotthaus
Keyword(s):  
Quantum Dot ◽  
Coulomb Blockade ◽  
Silicon Quantum Dot
Sign in / Sign up

Export Citation Format

Share Document