M. V. Chukalina | Searcharxiv

arXiv2007

Asymmetry with respect to the magnetic field direction in the interaction between the quantum states of two coupled superconducting rings

The interaction between the quantum states of two aluminum superconducting rings forming an 8-shape circular-asymmetric microstructure was examined under a threading magnetic flux and bias by an alternating current without a dc component. Quantum oscillations of the rectified dc voltage Vdc(B) as a function of magnetic field were measured in the 8-shape microstructure at various bias ac currents and temperatures close to critical. Fourier and wavelet analyses of Vdc(B) functions revealed the presence of various combination frequencies in addition to two ring fundamental frequencies, which suggests the interaction in the structure. Deviation of the Vdc(B) function from oddness with respect to the magnetic field direction was found for the first time.

cond-mat.supr-con↗

arXiv2005

Excited two-dimensional magnetopolaron states in quantum well of resonant tunnel junction

Tunnel spectroscopy is used to probe the electronic structure in GaAs quantum well of resonant tunnel junction over wide range of energies and magnetic fields normal to layers. Spin degenerated high Landau levels ($N=2\div7$) are found to be drastically renormalised near energies when the longitudinal optical-phonon ($\hbarω_{LO}$) and cyclotron energy ($\hbarω_{C}$) are satisfied condition $\hbarω_{LO}=m\hbarω_{C}$, where $m=1,2,3$. This renormalisation is attributed to formation of resonant magnetopolarons, i.e. mixing of high index Landau levels by strong interaction of electrons at Landau level states with LO-phonons.

cond-mat.mes-hall↗