COMPENSATION OF THE SPIN OF A QUANTUM DOT AT COULOMB BLOCKADE Kondo correlation with the contacts leads to a macro- scopic separation of the charge from the spin in the dot
نویسندگان
چکیده
We discuss a new entangled state that has been observed in the conduction across a quantum dot. At Coulomb blockade, electrons from the contacts correlate strongly to those localized in the dot, due to cotunneling processes. Because of the strong Coulomb repulsion on the dot, its electron number is unchanged w.r.to the dot in isolation, but the total spin is fully or partly compensated. In a dot with N = even at the singlet-triplet crossing, which occurs in large magnetic field, Kondo correlations lead to a total spin S = 1/2.
منابع مشابه
Bistability in the Electric Current through a Quantum-Dot Capacitively Coupled to a Charge-Qubit
We investigate the electronic transport through a single-level quantum-dot which is capacitively coupled to a charge-qubit. By employing the method of nonequilibrium Green's functions, we calculate the electric current through quantum dot at finite bias voltages. The Green's functions and self-energies of the system are calculated perturbatively and self-consistently to the second order of inte...
متن کاملTransport through Quantum Dots and Thekondo Problem
Transport through quantum dots with large level spacing and charging energy is considered. At low temperature and strong coupling to the leads, quantum uctuations and the Kondo eeect become important. They show up, e.g., as zero-bias anomalies in the current-voltage characteristics. We use a recently developed diagrammatic technique as well as a new real-time renormalization-group approach to d...
متن کاملSpin blockade in ground state resonance of a quantum dot
– We present measurements on spin blockade in a laterally integrated quantum dot. The dot is tuned into the regime of strong Coulomb blockade, confining ∼ 50 electrons. At certain electronic states we find an additional mechanism suppressing electron transport. This we identify as spin blockade at zero bias, possibly accompanied by a change in orbital momentum in subsequent dot ground states. W...
متن کاملControlled dephasing of a quantum dot in the Kondo regime.
Kondo correlation in a spin polarized quantum dot (QD) results from the dynamical formation of a spin singlet between the dot's net spin and a Kondo cloud of electrons in the leads, leading to enhanced coherent transport through the QD. We demonstrate here significant dephasing of such transport by coupling the QD and its leads to potential fluctuations in a nearby "potential detector." The qua...
متن کاملEnergy states and exchange energy of coupled double quantum dot in a magnetic field
The ground state energies of two interacting electrons confined in a coupled double quantum dot (DQD) presented in a magnetic field has been calculated by solving the relative Hamiltonian using variational and exact diagonalization methods. The singlet-triplet transitions in the angular momentum and spin of the quantum dot ground state had been shown .We have studied the magnetic field versus c...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2001