How Flatland works

74 material families, each with its crystal structure, a data sheet, how it is made and used, its open problems and its key references; 218 glossary terms; a step-by-step course; and four tracks that read the same field for a curious reader, a theoretician, an experimentalist and an engineer.

Three tools work across the catalogue: compare materials side by side, stack two layers to see their moiré and the supercells that fit both, and read all the open problems sorted by theme. The news, conference and prize pages follow the field as it moves.

The news is collected automatically about every six hours from 137 sources: 40 journal feeds, 19 science-news sites and 78 arXiv searches, all listed below. Every item links to the original and shows the publisher’s own title and abstract; Flatland writes no summaries of its own.

An item is kept only if it is about 2D materials. A word list decides that, and tags each item with the materials it concerns, the tracks it suits and how much background it assumes. Each tag records the words that set it, so a wrong one can be traced back and the list corrected. When several feeds carry the same article, it is shown once. Preprints are marked as not yet peer reviewed, and items leave the page after 540 days.

Every reference with a DOI is checked against Crossref each week: the DOI must resolve, and its title, year, first author, journal, volume and first page must match what the page says. A retracted or withdrawn paper fails the check; corrections are noted. The citation counts in the reference lists come from OpenAlex and are refreshed weekly too.

The same weekly run tests the links the research tracks give to codes, databases and facilities. Further checks list the sentences that go out of date on their own – “the largest so far”, “not yet” – for rereading, and the ideas the site uses without explaining them in the glossary.

Each of the 73 crystal models is built from a published structure, mostly from X-ray or neutron diffraction on bulk crystals, and its caption names the source. The few that are constructions – a twisted bilayer, an oxide interface – are built from measured lattices and say so.

The values under “How to recognise it”, on 27 material pages, come from published measurements: each table names its sources, and the laser where the paper gives it. The 18 photos of real samples come from Wikimedia Commons, each credited with its author and licence.

The catalogue and the glossary download as CSV files. Every crystal model saves as a CIF, XYZ or POSCAR file from its material page, with the source written into the file, and each material’s key references as BibTeX or RIS. News comes as an RSS feed, for the whole site and, from its page, for each material with recent news; the changes to the site as a feed of their own; What’s new lists them, newest first.

Flatland’s own texts and data – the catalogue, the glossary, the crystal models and the reference files – may be reused under the Creative Commons Attribution 4.0 licence (CC BY 4.0): share and adapt them, naming Flatland with a link. Not covered: the photos, each under the licence in its credit, and the news summaries, which belong to their publishers.

Journals (40): npj 2D Materials and Applications, Nature Nanotechnology, Nature Materials, Nature Electronics, Nature Physics, Nature Reviews Materials, npj Computational Materials, Nature Communications, Nature, Nature: Two-dimensional materials, Nature: Graphene, Physical Review Letters, Physical Review X, Physical Review Materials, Physical Review B, Physical Review Applied, APS Physics Magazine, 2D Materials (IOP), Nanotechnology (IOP), Journal of Physics: Materials, Journal of Physics: Condensed Matter, Advanced Materials, Advanced Functional Materials, Small, Advanced Electronic Materials, Advanced Optical Materials, Advanced Materials Interfaces, InfoMat, Carbon, Nano Today, Materials Today, Matter, ACS Nano, Nano Letters, Chemistry of Materials, ACS Applied Materials & Interfaces, Nanoscale, Journal of Materials Chemistry C, Materials Horizons, Science Advances.

Science news (19): Science News, Phys.org Nanomaterials, Phys.org Graphene, Phys.org Nanotechnology, Phys.org Condensed Matter, ScienceDaily Graphene, ScienceDaily Materials Science, ScienceDaily Nanotechnology, MIT News — Materials Science, AZoNano, New Scientist — Physics (no answer on the last run), Physics World, Graphene-Info, IEEE Spectrum — Semiconductors, IEEE Spectrum — Nanoclast, Semiconductor Engineering, TechXplore — Semiconductors, eeNews Europe, Electronics Weekly.

arXiv searches (78): Moiré & twistronics, TMDC monolayers, 2D growth & synthesis, MXenes, 2D devices & applied physics, Excitons in 2D, hBN quantum emitters, Elemental 2D (Xenes), 2D magnetism, 2D superconductivity theory, Machine learning for 2D materials, Moiré correlated phases, Fractional Chern insulators, GW–BSE and excitons in 2D, Sliding and 2D ferroelectricity, Topology in 2D, Defects and emitters from first principles, Electron–phonon and mobility, Janus monolayers, CVD and MOCVD growth, Bulk crystal growth (CVT, flux), MBE of layered materials, Transfer and heterostructure assembly, Raman and photoluminescence, Electron microscopy of defects, ARPES of 2D materials, 2D transistors and contacts, Magneto-optics of 2D magnets, 2D transistors (applied physics), Wafer-scale 2D materials, CMOS integration, back end of line and monolithic 3D, Contact engineering, Reliability of 2D devices, 2D memristors and neuromorphic hardware, Graphene integrated photonics, 2D membranes and nanofluidics, Kitaev magnets, Transition-metal trihalides, Chalcohalides, Transition-metal dihalides, Magnetic topological insulators, Thin iron chalcogenide superconductors, Layered oxyhalides, Titanium, zirconium and hafnium dichalcogenides, Vanadium and chromium dichalcogenides, Breathing-kagome niobium halides, Weyl and Dirac semimetal tellurides, Copper thiophosphate ferroelectrics, Chromium thiophosphate, Quasi-one-dimensional trichalcogenides, Trigonal PtBi₂, Tantalum nickel selenide, Bismuth oxyhalides, In₂Se₃ ferroelectric semiconductor, Bismuth oxyselenide, Kagome metals AV₃Sb₅, MoSi₂N₄ and the MA₂Z₄ family, Rare-earth tritellurides, Antimony chalcogenides, Chalcohalide chains SbSI and BiSI, Layered metal iodides PbI₂ and BiI₃, Nitride halides ZrNCl and HfNCl, Tin monoxide, Group IV-V layered semiconductors, Bismuth halide chains Bi₄Br₄, Van der Waals heavy fermion CeSiI, Mithrene and metal-organic chalcogenolates, Electride Ca₂N, Nodal-line superconductor PbTaSe₂, Magnetic topological insulator EuSn₂As₂, Colossal magnetoresistance ferrimagnet Mn₃Si₂Te₆, arXiv cond-mat.mes-hall, arXiv cond-mat.mtrl-sci, arXiv cond-mat.str-el, arXiv cond-mat.supr-con, arXiv physics.app-ph, arXiv physics.optics, arXiv cond-mat.other.