arXiv subjects

I. A. Shelykh

Publications and source records attributed to I. A. Shelykh.

194 records · Page 11Linked to original sources

arXiv2007

Comment on "Experimental Demonstration of the Time Reversal Aharonov-Casher Effect"

In a recent Letter, Bergsten and co-authors have studied the resistance oscillations with gate voltage and magnetic field in arrays of semiconductor rings and interpreted the oscillatory magnetic field dependence as Altshuler-Aronov-Spivak (AAS) oscillations and oscillatory dependence on gate voltage as the Aharonov-Casher (AC) effect. This Comment shows that Bergsten and co-authors incorrectly identified AAS effect as a source of resistance oscillations in magnetic field, that spin relaxation in their experimental setting is strong enough to destroy oscillatory effects of spin origin, and that the oscillations are caused by changes in carrier density and the Fermi energy by gate, and are unrelated to spin.

cond-mat.mes-hall↗

arXiv2006

Polarization multistability of cavity polaritons

New effects of polarization multistability and polarization hysteresis in a coherently driven polariton condensate in a semiconductor microcavity are predicted and theoretically analyzed. The multistability arises due to polarization-dependent polariton-polariton interactions and can be revealed in polarization resolved photoluminescence experiments. The pumping power required to observe this effect is of 4 orders of magnitude lower than the characteristic pumping power in conventional bistable optical systems.

cond-mat.other↗

arXiv2006

Nonlinear effects in spin relaxation of cavity polaritons

We present the general kinetic formalism for the description of spin and energy relaxation of the cavity polaritons in the framework of the Born-Markov approximation. All essential mechanisms of polaritons redistribution in reciprocal space together with final state bosonic stimulation are taken into account, from our point of view. The developed theory is applied to describe our experimental results on the polarization dynamics obtained in the polariton parametric amplifier geometry (pumping at so-called magic angle). We have experimentally confirmed that the anisotropy of the polariton-polariton interaction is responsible for the build up of the cross-linear polarisation of the signal. The long-living linear polarization is observed at zero detuning. Under elliptical pumping, we have directly measured in the time domain and modelled the effect of self-induced Larmor precession.

cond-mat.mes-hall↗

arXiv2006

Fractional form of the 0.7(2e2/h) feature

We present the first findings of the spin transistor effect in the Rashba gate-controlled ring embedded in the p-type self-assembled silicon quantum well that is prepared on the n-type Si (100) surface. The coherence and phase sensitivity of the spin-dependent transport of holes are studied by varying the value of the external magnetic field and the top gate voltage that are applied perpendicularly to the plane of the double-slit ring and revealed by the Aharonov-Bohm (AB) and Aharonov-Casher (AC) conductance oscillations, respectively. Firstly, the amplitude and phase sensitivity of the 0.7(2e2/h) feature of the hole quantum conductance staircase revealed by the quantum point contact inserted in the one of the arms of the double-slit ring are found to result from the interplay of the spontaneous spin polarization and the Rashba spin-orbit interaction (SOI). Secondly, the values of the AC conductance oscillations caused by the Rashba SOI are found to take the fractional form with both the plateaus and steps as a function of the top gate voltage.

cond-mat.mes-hall↗

arXiv2006

The conductance of the quantum wire touching the gated Aharonov-Bohm ring

We analyse the conductance of the Aharonov - Bohm (AB) one- dimensional quantum ring touching a quantum wire. The period of the AB oscillations is shown to be dependent strongly on the chemical potential and the Rashba coupling parameter that is in a good agreement with the studies of such a device prepared on the Si(100) surface.

cond-mat.mes-hall↗

arXiv2006

Optical Anisotropy and Pinning of the Linear Polarization of Light in Semiconductor Microcavities

We report a strong experimental evidence of the optical anisotropy in a CdTe-based microcavity: the polarization of light is pinned to one of the crystallographic axes independently on the polarization of the excitation. The polarization degree depends strongly on the excitation power, reaching almost 100 % in the stimulated regime. The relaxation time of the polarization is about 1 ns. We argue that all this is an effect of a splitting of the polariton doublet at k=0. We consider different sources for the splitting and conclude that the most likely one is optical birefringence in the mirrors and/or the cavity.

cond-mat.mtrl-sci↗

arXiv2006

The conductance of the gated Aharonov - Bohm ring touching a quantum wire

We analyse the conductance of the Aharonov-Bohm one-dimensional quantum ring touching a quantum wire. It is shown that in accordance with experimental data the period of the AB oscillations strongly depends on the chemical potential and the Rashba coupling parameter. The dependence of the conductance on the carrier's energy is shown to reveal the Fano resonances.

cond-mat.mes-hall↗

arXiv2006

Spin interference in silicon three-terminal one-dimensional rings

We present the first findings of the spin transistor effect in the Rashba gate-controlled ring embedded in the p-type self-assembled silicon quantum well that is prepared on the n-type Si (100) surface. The coherence and phase sensitivity of the spin-dependent transport of holes are studied by varying the value of the external magnetic field and the bias voltage that are applied perpendicularly to the plane of the double-slit ring. Firstly, the amplitude and phase sensitivity of the 0.7(2e^2/h) feature of the hole quantum conductance staircase revealed by the quantum point contact inserted in the one of the arms of the double-slit ring are found to result from the interplay of the spontaneous spin polarization and the Rashba spin-orbit interaction. Secondly, the quantum scatterers connected to two one-dimensional leads and the quantum point contact inserted are shown to define the amplitude and the phase of the Aharonov-Bohm and the Aharonov-Casher conductance oscillations.

cond-mat.mes-hall↗

arXiv2006

Quantum point contact with large localized spin: fractional quantization of the ballistic conductance

We analyze the conductance of the quantum point contact containing large localized spin J. The additional plateau is formed on a ballistic conductance staircase if only one propagating channel is rendered conducting. The conductance value at this plateau is shown to depend strongly on J and decrease from 3e^2/2h to e^2/h when J increases from 1/2 to infinity, which is in a good agreement with the experimental observations [D.J. Reilly, et al, Phys. Rev. B 63, 121311 (2001)].

cond-mat.mes-hall↗

arXiv2005

Quantum splitter controlled by Rashba spin-orbit interaction

We propose the mesoscopic device based on the Rashba spin orbit interaction (SOI) that contains a gated ballistic Aharonov-Bohm (AB) ring with incoming lead and two asymmetrically situated outgoing leads. The variations of the Rashba coupling parameter induced by the gate voltage applied to the AB ring is shown to cause the redistribution of the carrier flux between the outgoing leads and spin polarization of the outgoing currents, thus allowing the system to manifest the properties of the quantum splitter and spin filter.

cond-mat.mes-hall↗

arXiv2005

Spin interference in silicon one-dimensional rings

We present the first findings of the spin transistor effect caused by the Rashba gate-controlled ring embedded in the p-type self-assembled silicon quantum well that is prepared on the Si (100) surface. The coherence and phase sensitivity of the spin-dependent transport of holes are studied by varying the value of the external magnetic field and the gate voltage that are perpendicular to the plane of the double-slit ring. Firstly, the quantum scatterers connected to two one-dimensional leads and the quantum point contact inserted in the one of the arms of the double-slit ring are shown to define the amplitude and the phase of the Aharonov-Bohm and the Aharonov-Casher conductance oscillations. Secondly, the amplitude and phase sensitivity of the 0.7 feature of the hole quantum conductance staircase revealed by the quantum point contact inserted are found to result from the interplay of the spontaneous spin polarization and the Rashba spin-orbit interaction.

cond-mat.mes-hall↗

arXiv2004

Interplay of h/e and h/2e Oscillations in Gate-Controlled Aharonov-Bohm Rings

The spin-interference that is caused by the Rashba spin-orbit interaction in a gate-controlled Aharonov-Bohm ring is studied by the analysis of the conductance oscillations as a function of both the gate voltage and magnetic field. The scattering matrix approach is used to reveal the effect of the quantum scatterers connected to two one-dimensional leads on the phase of the transmission and reflection amplitudes. The variations of the transmission and reflection amplitudes that are caused by the quantum scatterers for the particles moving inside and outside rings are shown to define a parity of the and conductance oscillations.

cond-mat.mes-hall↗

arXiv2004

Light Mediated Superconducting Transistor

Bose-condensation of mass-less quasiparticles (photons) can be easily achieved at the room temperature in lasers. On the other hand, condensation of bosons having a non-zero mass requires usually ultra-low temperatures. Recently, it has been shown that polaritons, which are half-light-half-matter quasi-particles, may form condensed states at high temperatures (up to 300K). Polaritons composed by electron-hole pairs coupled to confined light modes in optical cavities may form a Bardeen-Cooper-Schriefer (BCS) superfluid. We propose a new transistor based on stimulated scattering of electron-hole pairs into the BCS polariton mode. A pn-junction embedded inside an optical cavity resonantly emits light into the cavity mode. If the cavity mode energy slightly exceeds the band-gap energy, it couples with electron-hole pairs with zero centre of mass wave-vector but non-zero wave-vector of relative motion. This creates a super-current in the plane of the structure. In an isotropic case, its direction is chosen by the system spontaneously. Otherwise, it is pinned to the external in-plane bias. We calculate the phase diagram for the electron-hole-polariton system.

cond-mat.mtrl-sci↗

arXiv2004

Spin Depolarization in Quantum Wires Polarized Spontaneously in a Zero Magnetic Field

The conditions for a spontaneous spin polarization in a quantum wire positioned in a zero magnetic field are analyzed under weak population of one-dimensional subbands that gives rise to the efficient quenching of the kinetic energy by the exchange energy of carriers. The critical linear concentration of carriers above which the quasi one-dimensional gas undergoes a complete spin depolarization is determined by the Hartree-Fock approximation. The dependence of the critical linear concentration on the concentration of carriers is defined to reveal the interplay of the spin depolarization with the evolution of the 0.7 (2e2/h) feature in the quantum conductance staircase from the e2/h to 3/2 (e2/h) values. This dependence is used to study the effect of the hole concentration on the 0.7 (2e2/h) feature in the quantum conductance staircase of the quantum wire prepared inside the p-type silicon quantum well using the split-gate technique. The 1D channel is demonstrated to be spin-polarized at the linear concentration of holes lower than the critical linear concentration, because the 0.7 (2e2/h) feature is close to the value of 0.5 (2e2/h) that indicates the spin degeneracy lifting for the first step of the quantum conductance staircase. The 0.7 (2e2/h) feature is found to take however its normal magnitude when the linear concentration of holes attains the critical value corresponding to the spin depolarization. The variations in the height of the 0.7 (2e2/h) feature observed in the hole quantum conductance staircase that is revealed by the p-type silicon quantum wire seem to be related to the evidences of the quantum conductance staircase obtained by varying the concentration of electrons in the 1D channel prepared inside the GaAs-AlGaAs heterojunction.

cond-mat.mes-hall↗