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Here we report on experiments performed by linear-dichroism angle resolved photoelectron spectroscopy (LD-ARPES) on septuple layers (SL) topological insulator GeBi2Te4. The linear dichroic signals, both for the valence band states and in the topologically protected surface state are interpreted as a probe of the symmetry of the states. The observation of a change in the LD-ARPES spectrum at the top of VB is attributed to the band parity inversion which is predicted by theory for all materials entering the topologically protected phase. Finally, the opening of a gap in the surface state dispersion along the non-high symmetry direction is reported. This is proposed to originated from the interaction between the surface state and the VB, leading to the formation of surface resonances. (C) 2018 Elsevier B.V. All rights reserved.

Here we report on experiments performed by linear-dichroism angle resolved photoelectron spectroscopy (LD-ARPES) on septuple layers (SL) topological insulator GeBi2Te4. The linear dichroic signals, both for the valence band states and in the topologically protected surface state are interpreted as a probe of the symmetry of the states. The observation of a change in the LD-ARPES spectrum at the top of VB is attributed to the band parity inversion which is predicted by theory for all materials entering the topologically protected phase. Finally, the opening of a gap in the surface state dispersion along the non-high symmetry direction is reported. This is proposed to originated from the interaction between the surface state and the VB, leading to the formation of surface resonances. (C) 2018 Elsevier B.V. All rights reserved.

The electronic structure of ZrTe5 has been matter of renewed interest aimed at clarifying, along with its topological character, the temperature dependence of the unusual transport properties of this material. Here, we report an extensive high resolution Angle Resolved Photoelectron Spectroscopy (ARPES) study unveiling a non-monotonic shift of the bands, when the sample temperature is varied between 16K and 300K. Moreover, the present conventional ARPES and circularly dichroic ARPES measurements reveal the presence of two states at the top of the valence band. The strong ARPES dichroic signal detected in proximity of the Fermi energy has been interpreted as the indication of the presence of spin polarized states, in agreement with the predicted strong topological character of this material. (c) 2016 Elsevier B.V. All rights reserved.

The electronic structure of ZrTe5 has been matter of renewed interest aimed at clarifying, along with its topological character, the temperature dependence of the unusual transport properties of this material. Here, we report an extensive high resolution Angle Resolved Photoelectron Spectroscopy (ARPES) study unveiling a non-monotonic shift of the bands, when the sample temperature is varied between 16K and 300K. Moreover, the present conventional ARPES and circularly dichroic ARPES measurements reveal the presence of two states at the top of the valence band. The strong ARPES dichroic signal detected in proximity of the Fermi energy has been interpreted as the indication of the presence of spin polarized states, in agreement with the predicted strong topological character of this material. (c) 2016 Elsevier B.V. All rights reserved.