Reversal of thermopower oscillations in mesoscopic Andreev interferometer
نویسنده
چکیده
We report on measurements of thermopower oscillations vs magnetic field in diffusive Andreev interferometer. Upon the increase of the dc current applied to the heater electrodes, the amplitude of these oscillations first increases then goes to zero as one would expect. Surprisingly the oscillations reappear at yet higher heater currents with their phase being π-shifted compared to low current values. Using direct measurements of temperature gradient we estimate the amplitude of the oscillations to be orders of magnitude lower than predicted by theory.
منابع مشابه
The symmetry of phase-coherent thermopower oscillations in Andreev interferometers
We study the thermopower of diffusive Andreev interferometers, which are hybrid loops with one normal-metal arm and one superconducting arm. The thermopower oscillates as a function of the magnetic flux through the loop with a fundamental period corresponding to one flux quantum Φ0 = h/2e. Unlike the electrical resistance oscillations and the thermal resistance oscillations, which are always sy...
متن کاملCoulomb blockade oscillations in the thermopower of open quantum dots.
We consider Coulomb blockade oscillations of thermoelectric coefficients of a single electron transistor based on a quantum dot strongly coupled to one of the leads. An analytic expression for the thermopower as a function of temperature T and the reflection amplitude r in the quantum point contact is obtained. Two regimes can be identified: T<>EC/r/2, where EC is the charging ene...
متن کاملDetermination of time-reversal symmetry breaking lengths in an InGaAs interferometer array.
Quantum interference oscillations due to the Aharonov-Bohm phase were measured in a ring interferometer array fabricated on a two-dimensional electron system in an InGaAs/InAlAs heterostructure. Coexisting oscillations with magnetic flux periodicity h/e and h/2e were observed and their amplitudes compared as function of applied magnetic field. The h/2e oscillations originate in time-reversed tr...
متن کاملTime reversal Aharonov–Casher effect using Rashba spin–orbit interaction
We propose a spin interferometer using Rashba spin–orbit interaction. A spin interference effect is demonstrated in small arrays of mesoscopic InGaAs rings. This spin interference is the time reversal Aharonov– Casher (AC) effect. The AC interference oscillations are controlled over several periods. This result shows evidence for electrical manipulation of the spin precession angle in an InGaAs...
متن کاملCoulomb blockade in metallic grains at large conductance
We study Coulomb blockade effects in the thermodynamic quantities of a weakly disordered metallic grain coupled to a metallic lead by a tunneling contact with a large conductance gT . We consider the case of broken time-reversal symmetry and obtain expressions for both the ensemble averaged amplitude of the Coulomb blockade oscillations of the thermodynamic potential and the correlator of its m...
متن کامل