直到丹尼爾·舍特曼的發(fā)現(xiàn)提出之前,，化學(xué)家曾一直將晶體定義為原子按照可重復(fù)的規(guī)則模式進(jìn)行排列的材料,。然而，在1982年,，以色列理工大學(xué)材料科學(xué)家舍特曼發(fā)現(xiàn),，一種鋁和錳的合金,，其原子按常規(guī)順序排列，但是不能重復(fù),。
此類“準(zhǔn)晶體”迫使化學(xué)家重新編寫了他們的教科書。最終,，2011年舍特曼因準(zhǔn)晶體的發(fā)現(xiàn)獲得諾貝爾化學(xué)獎,。自從發(fā)現(xiàn)準(zhǔn)晶體后，科學(xué)家也在自然界中發(fā)現(xiàn)了準(zhǔn)晶體,，而且工程師制造出多種多樣的準(zhǔn)晶體,，并將它們用于從刀片到不粘鍋涂料等各種產(chǎn)品中。
現(xiàn)在,，德國研究人員想出一種“栽培”超薄準(zhǔn)晶體薄膜的新方法,。正如他們近日于《自然》雜志在線報道的那樣，他們將一個鈦酸鋇（BaTiO3）薄膜層放置在六方晶格排列的鉑原子表面上,。一般而言,，BaTiO3原子會被排列成立方體形狀。但是,，兩個層次間原子排列的不協(xié)調(diào),，迫使BaTiO3將自己的原子排列成12面體。
如圖所示,，這個12面體的外環(huán)呈淺色,。在內(nèi)部，原子按照三角形,、正方形和菱形進(jìn)行排列,。研究人員表示，這種制造準(zhǔn)晶體的新方法可能帶來目前未曾被使用過的更多準(zhǔn)晶體品種,。(生物谷：Bioon.com)
生物谷推薦的英文摘要
Natute doi:10.1038/nature12514
Quasicrystalline structure formation in a classical crystalline thin-film system
Stefan Forster,Klaus Meinel,René Hammer,Martin Trautmann& Wolf Widdra
The discovery of quasicrystals1—crystalline structures that show order while lacking periodicity—forced a paradigm shift in crystallography. Initially limited to intermetallic systems1, 2, 3, 4, the observation of quasicrystalline structures has recently expanded to include ‘soft’ quasicrystals in the fields of colloidal and supermolecular chemistry5, 6, 7, 8, 9. Here we report an aperiodic oxide that grows as a two-dimensional quasicrystal on a periodic single-element substrate. On a Pt(111) substrate with 3-fold symmetry, the perovskite barium titanate BaTiO3 forms a high-temperature interface-driven structure with 12-fold symmetry. The building blocks of this dodecagonal structure assemble with the theoretically predicted Stampfli–G?hler tiling10, 11 having a fundamental length-scale of 0.69?nm. This example of interface-driven formation of ultrathin quasicrystals from a typical periodic perovskite oxide potentially extends the quasicrystal concept to a broader range of materials. In addition, it demonstrates that frustration at the interface between two periodic materials can drive a thin film into an aperiodic quasicrystalline phase, as proposed previously12. Such structures might also find use as ultrathin buffer layers for the accommodation of large lattice mismatches in conventional epitaxy13.
