Light-Tunable Surface State and Hybridization Gap in Magnetic Topological Insulator MnBi8Te13

MnBi8Te13 is an intrinsic ferromagnetic (FM) topological insulator with different complex surface terminations. Resolving the electronic structures of different termination surfaces and manipulation of the electronic state are important. Here, by using micrometer spot time- and angle-resolved photoemission spectroscopy (mu-TrARPES), we resolve the electronic structures and reveal the ultrafast dynamics upon photoexcitation. Photoinduced filling of the surface state hybridization gap is observed for the Bi2Te3 quintuple layer directly above MnBi2Te4 accompanied by a nontrivial shift of the surface state, suggesting light-tunable interlayer interaction. Relaxation of photoexcited electrons and holes is observed within 1-2 ps. Our work reveals photoexcitation as a potential control knob for tailoring the interlayer interaction and surface state of MnBi8Te13.

Automated summary

The electronic structures of different terminations of MnBi8Te13 were resolved using micrometer spot time- and angle-resolved photoemission spectroscopy, revealing ultrafast dynamics upon photoexcitation. The experiment observed photoinduced filling of the surface state hybridization gap and a nontrivial shift of the surface state, as well as relaxation of photoexcited electrons and holes within 1-2 ps. This work demonstrates photoexcitation as a potential control knob for tailoring the interlayer interaction and surface state of MnBi8Te13.