Short range proximity effect induced by exchange interaction in tunnel-coupled CdTe and (Cd,Mn)Te quantum wells
| Autor: | Vladimir N. Mantsevich, G. Karczewski, S. Chusnutdinow, M. Salewski, Yu. G. Kusrayev, N. V. Kozyrev, E. Kirstein, Igor Krivenko, Manfred Bayer, Tomasz Wojtowicz, V. K. Kalevich, M. M. Afanasiev, Dmitri R. Yakovlev, E. A. Zhukov |
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| Rok vydání: | 2020 |
| Předmět: |
Larmor precession
Physics Zeeman effect Condensed matter physics Exciton Exchange interaction 02 engineering and technology Electron Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology 01 natural sciences symbols.namesake 0103 physical sciences Proximity effect (superconductivity) symbols 010306 general physics 0210 nano-technology Quantum well Quantum tunnelling |
| Zdroj: | Physical Review B. 101 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.101.035301 |
| Popis: | The coherent spin dynamics of electrons in tunnel-coupled CdTe and (Cd,Mn)Te quantum wells (QWs) is studied by time-resolved pump-probe Kerr rotation. The coupled QWs have different thicknesses; the narrow one is doped by ${\mathrm{Mn}}^{2+}$ magnetic ions. A short range proximity effect between them is observed: the Zeeman splitting of electrons in the wide QW is given in addition to the intrinsic electron $g$ factor by the exchange interaction with the ${\mathrm{Mn}}^{2+}$ ions mediated by electron tunneling into the narrow QW. The exchange interaction strength scales with the ${\mathrm{Cd}}_{0.88}{\mathrm{Mg}}_{0.12}\mathrm{Te}$ barrier thickness separating the QWs. The Kerr rotation signal measured on the wide QW shows two close frequencies of electron spin Larmor precession in a transverse magnetic field. These components have very different spin dephasing times, 50 ps and 1 ns. The two frequencies originate from electrons in the wide QW being either part of an exciton or being resident. The proximity effect of the exciton electron is smaller due to the binding by Coulomb interaction, which decreases the tunneling to the narrow well. The experimental data are in good agreement with model calculations. |
| Databáze: | OpenAIRE |
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