Department of Physics, Oxford University, Clarendon Laboratory, Oxford, United Kingdom.
Phys Rev Lett. 2011 Oct 21;107(17):177402. doi: 10.1103/PhysRevLett.107.177402. Epub 2011 Oct 18.
We use time- and angle-resolved photoemission spectroscopy with sub-30-fs extreme-ultraviolet pulses to map the time- and momentum-dependent electronic structure of photoexcited 1T-TaS(2). This compound is a two-dimensional Mott insulator with charge-density wave ordering. Charge order, evidenced by splitting between occupied subbands at the Brillouin zone boundary, melts well before the lattice responds. This challenges the view of a charge-density wave caused by electron-phonon coupling and Fermi-surface nesting alone, and suggests that electronic correlations play a key role in driving charge order.
我们使用时间和角度分辨光电子能谱和亚 30 飞秒极紫外脉冲来绘制光激发的 1T-TaS(2)的时间和动量依赖的电子结构。这种化合物是一种二维莫特绝缘体，具有电荷密度波有序。电荷有序，表现为布里渊区边界占据子带之间的分裂，在晶格响应之前就很好地熔化了。这挑战了仅仅由电子-声子耦合和费米面嵌套引起的电荷密度波的观点，并表明电子相关起着关键作用，推动了电荷有序。
