This record contains the experimental results of our reinvestigation of the bulk and surface electronic properties of Cd3As2, a well-known material proposed to realize the 3D Dirac semimetal phase. By using polarization-based matrix element effects in photoemission, we reveal multiple bands crossing the Fermi level, characterized by different orbital character. Those states exhibit also largely different effective masses, and by combining alkali metal deposition and photon energy dependent ARPES, we report that the linearly dispersing band, which was previously interpreted as a bulk Dirac particle, is indeed a 2D surface Dirac state.

This record contains the results of the first experimental investigation of the change in the electron dynamics across the topological phase transition from the type-II Weyl semimetal phase of MoTe2 to the trivial phase. By using the capability of time-resolved ARPES to access the unoccupied density of states, we succeed in transiently populating the Weyl points, which are otherwise above the Fermi level and out of the reach of conventional ARPES. We observe a bottleneck in the electron dynamics when the Weyl points annihilate and gaps are opened in the high-temperature trivial phase. This interpretation is supported by the observation that, in the "sister" compound WTe2 the dynamics is not affected by the change in temperature, and it is always much slower, thus reflecting the larger energy separation between the valence and conduction band.

This record contains the experimental band structure of MoTe2. The material exhibits a structural phase transition at approximately 240 K, and in the low-temperature 1T' phase is expected to realize the type-II Weyl semimetal phase. In our data we compare the band structure and the Fermi surface in the topological and in the trivial (1T'') phase. We report the existence of large surface arc, which is persistent across the topological phase transition, and we conclude that its observation cannot be taken alone as a smoking gun of the Weyl semimetal phase. The study is completed by a spin-resolved ARPES study of the bulk electronic properties in the low-temperature topological phase

This record contains the experimental results of our reinvestigation of the bulk and surface electronic properties of Cd3As2, a well-known material proposed to realize the 3D Dirac semimetal phase. By using polarization-based matrix element effects in photoemission, we reveal multiple bands crossing the Fermi level, characterized by different orbital character. Those states exhibit also largely different effective masses, and by combining alkali metal deposition and photon energy dependent ARPES, we report that the linearly dispersing band, which was previously interpreted as a bulk Dirac particle, is indeed a 2D surface Dirac state.

This record contains the experimental band structure of MoTe2. The material exhibits a structural phase transition at approximately 240 K, and in the low-temperature 1T' phase is expected to realize the type-II Weyl semimetal phase. In our data we compare the band structure and the Fermi surface in the topological and in the trivial (1T'') phase. We report the existence of large surface arc, which is persistent across the topological phase transition, and we conclude that its observation cannot be taken alone as a smoking gun of the Weyl semimetal phase. The study is completed by a spin-resolved ARPES study of the bulk electronic properties in the low-temperature topological phase

This record contains the results of the first experimental investigation of the change in the electron dynamics across the topological phase transition from the type-II Weyl semimetal phase of MoTe2 to the trivial phase. By using the capability of time-resolved ARPES to access the unoccupied density of states, we succeed in transiently populating the Weyl points, which are otherwise above the Fermi level and out of the reach of conventional ARPES. We observe a bottleneck in the electron dynamics when the Weyl points annihilate and gaps are opened in the high-temperature trivial phase. This interpretation is supported by the observation that, in the "sister" compound WTe2 the dynamics is not affected by the change in temperature, and it is always much slower, thus reflecting the larger energy separation between the valence and conduction band.