Entropic stabilization of a structurally tolerant phase: The ionic phase of lithium alanate

Entropic stabilization of a structurally tolerant phase: The ionic phase of lithium alanate | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Entropic stabilization of a structurally tolerant phase: The ionic phase of lithium alanate Marco Krummenacher, Omer Tayfuroglu, Jonas Finkler, Hannes Huber, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4318358/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In materials simulations, formation energies can provide valuable information about the stability of different crystal polymorphs. However, to obtain a complete picture, it is often essential to go beyond simple energetics and include free energies into the analysis as many crystal phases are stabilized by entropic contributions and phase transitions at finite temperatures are common. Traditionally, free energies of crystalline solids are computed through an analysis of the phonon band structure which is calculated within the harmonic approximation considering only the crystalline unit cell and its replication. But also methods that go beyond the harmonic approximation consider only one periodic structure to calculate free energies. We show that such an approach can overlook substantial configurational free energy contributions and does not allow us to reach a well defined thermodynamic limit. To overcome these problems, it is necessary to generate large periodic cells that can represent not only the perfect crystalline structure but also a very large number of defect structures. Only with a configurational density of states that is well converged with respect to the size of the cell, it is possible to obtain reliable estimates of phase transition temperatures. We illustrate this effect for lithium alanate where the configurational entropy contribution of the structurally tolerant ionic phase reduces the transition temperature to the polymeric phase by 150 K. Physical sciences/Materials science/Theory and computation/Computational methods Physical sciences/Materials science/Theory and computation/Electronic structure Full Text Additional Declarations (Not answered) Supplementary Files alanatessupplementary.pdf Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4318358","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":299018175,"identity":"04e44d96-d8cd-40e5-9b8e-aea963837622","order_by":0,"name":"Marco Krummenacher","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABD0lEQVRIiWNgGAWjYPCCBGQW8wEGBoMDIA4bsVrYEkjWwmMApHFr0W0/+/DDB4a0fINrpxMfF9TY5fFLn/kmXVBwR16+gfnZAyxazM6kG0vOYMix3HA7d7PxjGPJxZJ9udukZxg8M9xwgM3cAJuWA2lszDwMFQYGt4EqedgOJG44wwtkGBxm3MDAwyaBTcv5Z3At23/z/DuQuP8MzzOQFvv5DTi03ADbkgO2hZm3DWgLDw8bSEtiwwFcWp4xS84wSDOQBPpFmrcvOXHGGTZjax6DZ8kbDrOZYXdYGuOHDxXJBny3czd+5vlml9jfw/zwNs+fO7bz25ufYdMCAdgCBpgKcKofBaNgFIyCUUAAAAC7kWGUHRITPQAAAABJRU5ErkJggg==","orcid":"","institution":"University of Basel","correspondingAuthor":true,"prefix":"","firstName":"Marco","middleName":"","lastName":"Krummenacher","suffix":""},{"id":299018176,"identity":"bb01c758-084f-4ea6-9ca7-7a065f27cad1","order_by":1,"name":"Omer Tayfuroglu","email":"","orcid":"","institution":"Koc University","correspondingAuthor":false,"prefix":"","firstName":"Omer","middleName":"","lastName":"Tayfuroglu","suffix":""},{"id":299018177,"identity":"f5bf789c-2420-4fb5-a991-bc0649d734fc","order_by":2,"name":"Jonas Finkler","email":"","orcid":"","institution":"Aalborg University","correspondingAuthor":false,"prefix":"","firstName":"Jonas","middleName":"","lastName":"Finkler","suffix":""},{"id":299018178,"identity":"b410b0b8-66b9-4f40-9deb-52e688552171","order_by":3,"name":"Hannes Huber","email":"","orcid":"","institution":"University of Basel","correspondingAuthor":false,"prefix":"","firstName":"Hannes","middleName":"","lastName":"Huber","suffix":""},{"id":299018179,"identity":"ae5cee06-8c47-427d-8d64-b25a06c1c1a9","order_by":4,"name":"Stefan Goedecker","email":"","orcid":"https://orcid.org/0000-0002-3580-4186","institution":"University of Basel","correspondingAuthor":false,"prefix":"","firstName":"Stefan","middleName":"","lastName":"Goedecker","suffix":""}],"badges":[],"createdAt":"2024-04-24 12:50:34","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4318358/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4318358/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":58024211,"identity":"c18c955b-9668-421e-aa34-db29ba0c1217","added_by":"auto","created_at":"2024-06-10 06:03:25","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2254767,"visible":true,"origin":"","legend":"","description":"","filename":"alanates.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4318358/v1_covered_c79e0099-f57a-4540-a0d2-9a722883c1c5.pdf"},{"id":56229316,"identity":"f6174394-762b-4143-89da-2404d6d67146","added_by":"auto","created_at":"2024-05-10 06:53:27","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1318764,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"alanatessupplementary.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4318358/v1/f4bbcad615d56074ab2a73a5.pdf"}],"financialInterests":"(Not answered)","formattedTitle":"Entropic stabilization of a structurally tolerant phase: The ionic phase of lithium alanate","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4318358/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4318358/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"In materials simulations, formation energies can provide valuable information about the stability of different crystal polymorphs. 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