Bykov Maxim, Fedotenko Timofey, Chariton Stella, Laniel Dominique, Glazyrin Konstantin, Hanfland Michael, Smith Jesse S, Prakapenka Vitali B, Mahmood Mohammad F, Goncharov Alexander F, Ponomareva Alena V, Tasnádi Ferenc, Abrikosov Alexei I, Bin Masood Talha, Hotz Ingrid, Rudenko Alexander N, Katsnelson Mikhail I, Dubrovinskaia Natalia, Dubrovinsky Leonid, Abrikosov Igor A
The Earth and Planets Laboratory, Carnegie Institution for Science, Washington, D.C. 20015, USA.
College of Arts and Science, Howard University, Washington, D.C. 20059, USA.
Phys Rev Lett. 2021 Apr 30;126(17):175501. doi: 10.1103/PhysRevLett.126.175501.
High-pressure chemistry is known to inspire the creation of unexpected new classes of compounds with exceptional properties. Here, we employ the laser-heated diamond anvil cell technique for synthesis of a Dirac material BeN_{4}. A triclinic phase of beryllium tetranitride tr-BeN_{4} was synthesized from elements at ∼85 GPa. Upon decompression to ambient conditions, it transforms into a compound with atomic-thick BeN_{4} layers interconnected via weak van der Waals bonds and consisting of polyacetylene-like nitrogen chains with conjugated π systems and Be atoms in square-planar coordination. Theoretical calculations for a single BeN_{4} layer show that its electronic lattice is described by a slightly distorted honeycomb structure reminiscent of the graphene lattice and the presence of Dirac points in the electronic band structure at the Fermi level. The BeN_{4} layer, i.e., beryllonitrene, represents a qualitatively new class of 2D materials that can be built of a metal atom and polymeric nitrogen chains and host anisotropic Dirac fermions.
高压化学能够激发具有特殊性质的新型化合物的产生。在此，我们采用激光加热金刚石对顶砧技术合成了狄拉克材料BeN₄。在约85 GPa的压力下，由元素合成了四方氮化铍tr-BeN₄的三斜相。减压至环境条件时，它转变为一种化合物，该化合物具有通过弱范德华键相互连接的原子厚度的BeN₄层，由具有共轭π体系的聚乙炔类氮链和处于平面正方形配位的Be原子组成。对单个BeN₄层的理论计算表明，其电子晶格由略微扭曲的蜂窝状结构描述，让人联想到石墨烯晶格，并且在费米能级的电子能带结构中存在狄拉克点。BeN₄层，即铍氮烯，代表了一类全新的二维材料，它可以由金属原子和聚合物氮链构成，并容纳各向异性的狄拉克费米子。
