Electronic structure of (GaAs)1-xGe2: The relative importance of short-range and long-range order

Xanthakis, JP

dc.contributor.author	Xanthakis, JP	en
dc.date.accessioned	2014-03-01T01:08:47Z
dc.date.available	2014-03-01T01:08:47Z
dc.date.issued	1992	en
dc.identifier.issn	0953-8984	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/10688
dc.subject.classification	Physics, Condensed Matter	en
dc.subject.other	PHASE-TRANSITION	en
dc.subject.other	SOLID-SOLUTIONS	en
dc.subject.other	ALLOYS	en
dc.subject.other	(GASB)1-XGE2X	en
dc.subject.other	APPROXIMATION	en
dc.subject.other	CRYSTALLINE	en
dc.subject.other	DISORDER	en
dc.subject.other	SYSTEM	en
dc.subject.other	GROWTH	en
dc.subject.other	STATES	en
dc.title	Electronic structure of (GaAs)1-xGe2: The relative importance of short-range and long-range order	en
heal.type	journalArticle	en
heal.identifier.primary	10.1088/0953-8984/4/44/018	en
heal.identifier.secondary	http://dx.doi.org/10.1088/0953-8984/4/44/018	en
heal.identifier.secondary	018	en
heal.language	English	en
heal.publicationDate	1992	en
heal.abstract	We calculate the electronic structure of (GaAs)1-xGe2x, for which there are contradicting theories of the short-range structure. To investigate the latter we use the cluster-Bethe-lattice method and the configuration-averaging technique of Gomez-Santos and Verges which can take into account diagonal and off-diagonal disorder as well as disorder in the short-range order parameters. Our results are in good agreement with XPS spectra, and band gap, EXAFS and x-ray diffraction measurements. They point to models in which (i) no As-As or Ga-Ga bands exist, (ii) there is perfect coordination around each atom provided the atoms are not near grain boundaries and (iii) the fraction of antisites is very low for x < 0.2 and then quickly goes to 0.5 at the critical value x(c) at which the zincblende-to-diamond transition occurs. Furthermore we have strong evidence that short-range order is the dominant factor in the formation of not only the band gap, as reported previously, but also the valence band density of states, at least for x < x(c). By comparison with other calculations and experiments we show that the VCA breaks down for this class of alloys, and even the single-site CPA may be inadequate in some cases.	en
heal.publisher	IOP PUBLISHING LTD	en
heal.journalName	Journal of Physics: Condensed Matter	en
dc.identifier.doi	10.1088/0953-8984/4/44/018	en
dc.identifier.isi	ISI:A1992JX09800018	en
dc.identifier.volume	4	en
dc.identifier.issue	44	en
dc.identifier.spage	8573	en
dc.identifier.epage	8584	en