论文标题
$ ta_2nise_5 $中的非库仑强孔结合，由时间和角度分辨光发射光谱揭示
Non-Coulomb strong electron-hole binding in $Ta_2NiSe_5$ revealed by time- and angle-resolved photoemission spectroscopy
论文作者
论文摘要
我们在超快的激光激光脉冲激发后，揭示了\ tns中的超快纯电子相变。具体而言，强烈电子孔结合的顺序参数通过增强的泵脉冲收缩，并且在临界泵通量上方，在没有超快的结构过渡的情况下，在实验上鉴定出光启用的半金属金属状态。另外，确定了\ tns〜中的裸价和传统带以及有效的激子结合能。这些发现和详细的分析表明，在$ TA_2NISE_5 $中裸露的非平衡半金属相位，并且强大的电子孔结合不能仅由库仑相互作用驱动。
We reveal an ultrafast purely electronic phase transition in \TNS, which is a plausible excitonic insulator, after excited by an ultrafast infrared laser pulse. Specifically, the order parameter of the strong electron-hole binding shrinks with enhancing the pump pulse, and above a critical pump fluence, a photo-excited semimetallic state is experimentally identified with the absence of ultrafast structural transition. In addition, the bare valence and conduction bands and also the effective exciton binding energy in \TNS~are determined. These findings and detailed analysis suggest a bare nonequilibrium semimetallic phase in $Ta_2NiSe_5$ and the strong electron-hole binding cannot be exclusively driven by Coulomb interaction.
