Effective-mass superlattice: surface states and zero energy gaps

✍ Scribed by R Kucharczyk; M Stȩślicka

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 349 KB
• Volume: 48
• Category: Article
• ISSN: 0042-207X
• DOI: 10.1016/s0042-207x(96)00264-3

✦ Synopsis

The electronic structure of a terminated effective-mass superlattice (EMSL) is investigated taking into account the effect of the EMSL surface (i.e. the EMSUsubstrate interface). Special attention is paid to the conditions under which two neighbouring miniband edges cross each othel; which results in the vanishing of a corresponding mini-gap for certain EMSL bulk parameters (the so-called zero energy gap conditions). This is shown to influence considerably the surface electronic structure of EMSL and, in particulal; to affect the existence of surface states. lt is found that usually a surface state appears within one of the mini-gaps opening at the bulk band crossing point, so this mini-gap does not effectively exist, while the other mini-gap exhibits no surfacerelated features and, therefore, is well defined. The importance of the obtained results for the device applications of EMSL is pointed out.