Publications by Philipp Aebi | EPFL Graph Search

Local resilience of the 1T-TiSe2 charge density wave to Ti self-doping

Helmuth Berger, Philipp Aebi, Elia Razzoli

In Ti-intercalated self-doped 1T-TiSe2 crystals, the charge density wave (CDW) superstructure induces two nonequivalent sites for Ti dopants. Recently, it has been shown that increasing Ti doping dramatically influences the CDW by breaking it into phase-sh ...

Amer Physical Soc2017

Short-range phase coherence and origin of the 1T-TiSe2 charge density wave

Helmuth Berger, Philipp Aebi, Elia Razzoli

The impact of variable Ti self-doping on the 1T-TiSe2 charge density wave (CDW) is studied by scanning tunneling microscopy. Supported by density functional theory, we show that agglomeration of intercalated-Ti atoms acts as preferential nucleation centers ...

Amer Physical Soc2016

Evolution of the charge density wave superstructure in ZrTe3 under pressure

Helmuth Berger, Philipp Aebi, Corsin Battaglia

The material ZrTe3 is a well-known example of an incommensurate periodic lattice distortion (PLD) at low temperatures due to a charge density wave (CDW). Previous studies have found a sharp boundary as a function of pressure between CDW below 5 GPa and bul ...

Amer Physical Soc2016

Three-dimensional momentum-resolved electronic structure of 1T-TiSe2: A combined soft-x-ray photoemission and density functional theory study

Helmuth Berger, Philipp Aebi, Elia Razzoli, Thorsten Schmitt

1T-TiSe2 is a quasi-two-dimensional transition metal dichalcogenide, which exhibits a charge density wave transition at a critical temperature of similar to 200 K as well as low-temperature superconductivity induced by pressure or intercalation. The electr ...

Amer Physical Soc2015

Scanning tunneling microscopy of the charge density wave in 1T-TiSe2 in the presence of single atom defects

Helmuth Berger, Philipp Aebi

We present a detailed low-temperature scanning tunneling microscopy (STM) study of the commensurate charge density wave (CDW) in 1T-TiSe2 in the presence of single atom defects. We find no significant modification of the CDW lattice in single crystals with ...

Amer Physical Soc2015

Tuning electronic correlations in transition metal pnictides: Chemistry beyond the valence count

Philipp Aebi, Joël Mesot, Elia Razzoli, Thorsten Schmitt

The effects of electron-electron correlations on the low-energy electronic structure and their relationship with unconventional superconductivity are central aspects in the research on iron-based pnictide superconductors. Here we use soft x-ray angle-resol ...

Amer Physical Soc2015

Doping Nature of Native Defects in 1T-TiSe2

Helmuth Berger, Philipp Aebi

The transition-metal dichalcogenide 1T-TiSe2 is a quasi-two-dimensional layered material with a charge density wave (CDW) transition temperature of T-CDW approximate to 200 K. Self-doping effects for crystals grown at different temperatures introduce struc ...

Amer Physical Soc2014

Mapping of Electron-Hole Excitations in the Charge-Density-Wave System 1T-TiSe2 Using Resonant Inelastic X-Ray Scattering

Helmuth Berger, Philipp Aebi, Thorsten Schmitt

In high-resolution resonant inelastic x-ray scattering at the Ti L edge of the charge-density-wave system 1T-TiSe2, we observe sharp low energy loss peaks from electron-hole pair excitations developing at low temperature. These excitations are strongly dis ...

2012

Probing the exciton condensate phase in 1T-TiSe2 with photoemission

Helmuth Berger, Philipp Aebi

We present recent results obtained using angle-resolved photoemission spectroscopy performed on 1T-TiSe2. Emphasis is put on the peculiarity of the bandstructure of TiSe2 compared to other transition metal dichalcogenides, which suggests that this system i ...

2010

Spontaneous exciton condensation in 1T-TiSe2: BCS-like approach

Helmuth Berger, László Forró, Philipp Aebi, Corsin Battaglia

Recently we found strong evidence in favor of a BCS-like condensation of excitons in 1T-TiSe2 [Cercellier , Phys. Rev. Lett. 99, 146403 (2007)]. Theoretical photoemission intensity maps have been generated by the spectral function calculated within the exc ...

2009

Fermi surface of layered compounds and bulk charge density wave systems

Helmuth Berger, Philipp Aebi, Corsin Battaglia

A review is given of recent angle-resolved photoemission (ARPES) experiments and analyses on a series of layered charge density wave materials. Important aspects of ARPES are recalled in view of its capability for bulk band, Fermi surface and spectral func ...

2007