The Neutral–Ionic Phase Transition

Dear Colleagues,

The neutral–ionic phase transition was discovered in mixed-stack charge-transfer crystals almost 40 years ago. The transition, induced by temperature, pressure or light, involves two interrelated instabilities: (a) the crossover between a band-insulator (the neutral phase) and a Mott-insulator (the ionic phase), through a marginally metallic state; and (b) the lattice dimerization induced by a pure-Peierls mechanism close to the neutral–ionic interface and by a spin-Peierls mechanism far in the ionic regime. The subtle interplay between strongly correlated electrons and phonons in reduced dimensions drives the appearance of multiple competing phases, divergent responses, collective phenomena, ferroelectricity, multiferroicity, anomalous metallic states, etc., making the neutral–ionic phase transition and related materials an interesting playground for theoretical and experimental investigations.

The Special Issue will provide an international forum to cover a broad description of theoretical and experimental studies on the phenomenology of the transition, its mechanism and the properties of related materials. Scientists working in a wide range of disciplines are invited to contribute with original papers or short reviews on their activity in the field. The topics summarized under the keywords broadly cover the greater number of relevant sub-topics.

Prof. Dr. Anna Painelli
Guest Editor

Prof. Dr. Alberto Girlando
Co-Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2100 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.