Reuse of AIP material Single copies of individual articles may be made for private use or research. Authorization is given to copy articles beyond the free use permitted under Sections 107 and 108 of the U.S. Copyright Law, provided that the copying fee of $30.00 per copy per article is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, USA, http://www.copyright.com. For classroom use fees, contact CCC’s Academic Permission Service. (Note: You will need to refer to the publication by its ISSN as listed above.) Authorization does not extend to systematic or multiple reproduction, to copying for promotional purposes, to electronic storage or distribution, or to republication in any form. In all such cases, specific written permission from AIP must be obtained. Permission is granted to quote from an AIP publication with the customary acknowledgment of the source. Republication of an article or portions thereof (e.g., excerpts of greater than 400 words, figures, tables, etc.) in original form or in translation, as well as other types of reuse (such as use in course packs or electronic reserves) require formal permission from AIP and may be subject to fees. Although it is not a legal requirement for permission, as a courtesy, an author of the original article should be informed of any request for republication/reuse. http://publishing.aip.org/authors/rights-and-permissions