Lithuanian Journal of Physics article / Lietuvos fizikos žurnalo straipsnis

[PDF] http://dx.doi.org/10.3952/lithjphys.48211

Open access article / Atviros prieigos straipsnis

Lith. J. Phys. 48, 163–176 (2008)

SPIN PROPERTIES OF FREE ELECTRONS AND HOLES IN Hg_1–_xCd_xTe/CdTe QUANTUM WELL
A. Dargys
Semiconductor Physics Institute, A. Goštauto 11, LT-01108 Vilnius, Lithuania
E-mail: dargys@pfi.lt

Received 17 February 2008; accepted 9 June 2008

Spin properties of Hg_1–_xCd_xTe/CdTe quantum wells (QW) with inverted energy bands are considered using eight-band k·p Hamiltonian. The spin splitting of doubly degenerate bands (Kramers pairs) was included via either Rashba or external voltage Hamiltonians. The spin surfaces, which describe the average spin as a function of spin direction of a ballistic 2D charge carrier, in general, are shown to be ellipsoidal rather than spherical. In extreme cases the spin surfaces may reduce to disk, line, or Bloch sphere. Characteristic shapes of the spin surfaces at different wave vectors and QW composition x are presented in a form of graphs in the spin space.

Keywords: spintronics, spin–orbit coupling, spin models, II–VI semiconductors, spin-FET

PACS: 85.75.-d, 85.75.Hh, 75.10.Hk, 73.61.Ga

KVANTINIO Hg_1–_xCd_xTe/CdTe ŠULINIO LAISVŲJŲ ELEKTRONŲ BEI SKYLIŲ SUKINIO SAVYBĖS
A. Dargys
Puslaidininkių fizikos institutas, Vilnius, Lietuva

Pasitelkus aštuonių juostų k·p hamiltonianą, išnagrinėtos Hg_1–_xCd_xTe/CdTe kvantinių šulinių su invertuotomis energijos juostomis sukinio savybės. Energijos juostų suskilimas, susijęs su sukinio laisvės laipsniu ir Kramerso poromis, buvo įskaitytas arba per Rashbos hamiltonianą, arba per išorinio lauko hamiltonianą. Išnagrinėti sukinio paviršių, kurie nusako sukinio dydžio priklausomybę nuo jo krypties, pavidalai. Parodyta, kad balistinių dvimačių elektronų sukinio paviršiai bendru atveju turį elipsoidinį, o ne labiau įprastą sferinį pavidalą. Ribiniais atvejais sukinio paviršiai gali transformuotis į diską, tiesę arba Blocho sferą. Grafiškai pateiktos dvimačių elektronų ir skylių sukinio paviršių formos sukinio erdvėje, esant įvairiems laisvojo krūvininko bangos vektoriams ir skirtingoms kvantinį šulinį sudarančio junginio Hg_1–_xCd_xTe sudėtims.

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