ERA-Chemistry: Spin-polarized topological insulators under pressure

尽管固体的可压缩性很低，但热力学参数压力可以显著影响化合物的稳定性、它们的结构和性质。在本提案中，我们将解决材料的高压改性问题，这些材料是固态物理学前沿研究的焦点，即拓扑绝缘体（TI）。这些最近发现的非磁性材料代表了一种新的物质状态，可以在正常条件下实现量子自旋霍尔态。这种状态支持体表面上空间分离的自旋极化通道，可以独立控制，并且可以在不发生退相干的情况下传输信息。磁掺杂后，TI可以表现出量子化的电流而不耗散，这有望在标准条件下实现量子计算的突破。确认的TI数量非常有限。一些理论研究表明有可能在压力下获得新的TI，但到目前为止，补充的实验工作非常缺乏。至于已知TI的磁性掺杂，常压下的实验迄今为止已经产生非常适度的取代率（2至5at.%）。在几乎不受控制的合成条件下。为了填补这些空白，我们建议：（a）探索选定的TI候选人的结构演变，e。G.层状异质结构，例如BiTeI、（Bi 2）n（BiTeI）m、（Bi 2）n（Bi 2 Te 3）m、（BiTeI）n（Bi 2 Te 3）m（m，n大于或等于1）在压力下;（B）探索在已确认的TI中磁性替代Bi和磁性嵌入的可能性（Bi 2 Te 3，Bi 2Se 3）和上述Ti-候选物在压力下;（Cu、Mn、Fe、Cr、V）和稀土元素（Ce、Gd）;（c）在高压条件下寻找BiMX和SbMX（M = S、Se、Te，X = Cl、Br、I）的新的、可能亚稳态的结构修饰。拟议的研究将通过增加TI的数量，特别是磁性掺杂的数量，对固态化学和物理学做出重大贡献。

Despite the low compressibility of solids, the thermodynamic parameter pressure can notably influence the stability of compounds, their structure and properties. In this proposal we are going to tackle high-pressure modifications of materials that are in focus of the cutting-edge research in solid-state physics, namely topological insulators (TIs). These recently discovered non-magnetic materials represent a new state of matter that enables the quantum spin Hall state at normal conditions. This state supports spatially-separated spin-polarized channels on the bulk surface that can be controlled independently and can transmit information without decoherence. Upon magnetic doping, TIs can exhibit quantized electric current without dissipation, which promises breakthroughs in realization of quantum computing at standard conditions. The number of confirmed TIs is very limited. Some theoretical studies indicate a possibility to obtain new TIs under pressure, but the complementary experimental effort has so far been very scarce. As for magnetic doping of known TIs, experiments under normal pressure have so far yielded very modest substitution rates (2 to 5 at.%) under barely controlled synthetic conditions. In order to fill in these gaps we propose: (a) to explore structural evolution of selected TI-candidates, e. g. layered heterostructures such as BiTeI, (Bi2)n(BiTeI)m, (Bi2)n(Bi2Te3)m, (BiTeI)n(Bi2Te3)m (m, n greater or equal 1) under pressure; (b) to explore possibilities of magnetic substitution for Bi and magnetic intercalation in the confirmed TIs (Bi2Te3, Bi2Se3) and the abovementioned TI-candidates under pressure; 3d-metals (Cu, Mn, Fe, Cr, V) and rare-earth elements (Ce, Gd) will be investigated first; (c) to search for new, probably metastable, structural modifications of BiMX and SbMX, M = S, Se, Te, X = Cl, Br, I, under high-pressure conditions. The proposed research would contribute significantly to solid-state chemistry and physics by increasing the number of TIs and, especially, magnetically-doped ones.