Publications associées à Normal state bottleneck and nematic fluctuations from femtosecond quasiparticle relaxation dynamics in Sm(Fe,Co)AsO

Electrons leave the flatland: out-of-plane charge dynamics in layered materials

The goal of this thesis is to explore the "neglected" third dimension of layered materials, by studying the interlayer charge dynamics through dc conductivity, optical spectroscopy and ab-initio calculations. This project was designed to respond to the gro ...

EPFL2020

Manipulating topological spin textures in multiferroic and polar materials

Jan Hugo Dil

The possibility to manipulate spin textures is of central importance for their utilisation in functional materials. Here it will be shown how the resulting changes in the spin texture of the electronic structure can directly be imaged by spin- and angle-re ...

SPIE2020

Probing the reconstructed Fermi surface of antiferromagnetic BaFe2As2 in one domain

Timur Kim

A fundamental part of the puzzle of unconventional superconductivity in the Fe-based superconductors is the understanding of the magnetic and nematic instabilities of the parent compounds. The issues of which of these can be considered the leading instabil ...

Springer2019

Electric field exfoliation and high-T-C superconductivity in field-effect hole-doped hydrogenated diamond (111)

Thibault Daniel Pierre Sohier

We investigate the possible occurrence of field-effect induced superconductivity in the hydrogenated (111) diamond surface by first-principles calculations. By computing the band alignment between bulk diamond and the hydrogenated surface, we show that the ...

2019

Energy dependent structure of Xe ion tracks in YBCO and the effect on the superconductive properties in magnetic fields

Philippe Buffat, Elena Suvorova Buffat

The morphology and structure of damaged regions (tracks) produced by swift heavy 167, 77, and 46 MeV 132Xe23+ ions in YBCO-based second generation industrial high temperature superconductors wires (2G HTS) were studied using transmission electron microscop ...

2019

Time-Reversal Symmetry Breaking in Re-Based Superconductors

Joël Mesot, Johan Juul Chang

To trace the origin of time-reversal symmetry breaking (TRSB) in Re-based superconductors, we performed comparative muon-spin rotation and relaxation (mu SR) studies of superconducting noncentrosymmetric Re0.82Nb0.18 (T-c = 8.8 K) and centrosymmetric Re (T ...

AMER PHYSICAL SOC2018

Scaling of the superconducting gap with orbital character in FeSe

Timur Kim

We use high-resolution angle-resolved photoemission spectroscopy to map the three-dimensional momentum dependence of the superconducting gap in FeSe. We find that on both the hole and electron Fermi surfaces, the magnitude of the gap follows the distributi ...

2018

High-energy electronic interaction in the 3d band of high-temperature iron-based superconductors

Helmuth Berger, Maryna Viazovska

One of the most unique and robust experimental facts about iron-based superconductors is the renormalization of the electronic band dispersion by factor of 3 and more near the Fermi level. Obviously related to the electron pairing, this prominent deviation ...

2017

Pressure-induced superconductivity in the giant Rashba system BiTeI

Helmuth Berger

At ambient pressure, BiTeI exhibits a giant Rashba splitting of the bulk electronic bands. At low pressures, BiTeI undergoes a transition from trivial insulator to topological insulator. At still higher pressures, two structural transitions are known to oc ...

Iop Publishing Ltd2017

Spectroscopic Studies of the Electronic Structure in Layered Cuprates and Ruthenates

Claudia Giuseppina Fatuzzo

In materials where electrons interact strongly, a number of exotic and exciting phenomena arise. The mechanisms at the base of many of these phenomena remain debated, as strongly correlated electron physics represents one of the biggest challenges for mode ...

EPFL2017

Electronic Phase Separation and Dramatic Inverse Band Renormalization in the Mixed-Valence Cuprate LiCu2O2

Helmuth Berger, Philippe Bugnon, Marco Grioni, Arnaud Magrez, Luca Moreschini, Simon Karl Moser, Gianmarco Gatti

We measured, by angle-resolved photoemission spectroscopy, the electronic structure of LiCu2O2, a mixed-valence cuprate where planes of Cu(I) (3d(10)) ions are sandwiched between layers containing one-dimensional edge-sharing Cu(II) (3d(9)) chains. We find ...

Amer Physical Soc2017

Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4

Marco Grioni, Henrik Moodysson Rønnow, Simon Karl Moser, Johan Juul Chang, Claudia Giuseppina Fatuzzo, Gianmarco Gatti

A paradigmatic case of multi-band Mott physics including spin-orbit and Hund's coupling is realized in Ca2RuO4. Progress in understanding the nature of this Mott insulating phase has been impeded by the lack of knowledge about the low-energy electronic str ...

Nature Research2017

Single crystals of superconducting SmFeAsOHx: Structure and properties

László Forró, Richard Gaal, Alla Arakcheeva, Sergiy Katrych, Janusz Andrzej Karpinski, Andrea Pisoni, Ping Huang, Péter Krisztián Matus

We report the synthesis, structure, and superconducting properties of single crystals of SmFeAsOHx. The crystals were grown at high pressure and high temperature using a cubic anvil technique. H-1-NMR studies confirm the presence of H atoms in the samples. ...

Amer Physical Soc2016

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

Superconductivity in semimetallic Bi3O2S3

Henrik Moodysson Rønnow, Peter Babkevich, Lin Yang, David Parker

Here we report a further investigation on the thermodynamic and transport properties, and an assessment of theoretical calculations, for the BiS2- layered Bi3O2S3 superconductor. The polycrystalline sample is synthesized with a superconducting transition t ...

American Physical Society2015

High-temperature superconductivity from fine-tuning of Fermi-surface singularities in iron oxypnictides

In the family of the iron-based superconductors, the REFeAsO-type compounds (with RE being a rare-earth metal) exhibit the highest bulk superconducting transition temperatures (T-c) up to 55 K and thus hold the key to the elusive pairing mechanism. Recentl ...

Nature Publishing Group2015

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

The nature of the quasiparticles in two benchmark transition metal oxides : a spectroscopic study of anatase TiO₂ and tetragonal CuO

Simon Karl Moser

Transition metal oxides (TMOs) are emerging strong players in many domains, ranging from superconductivity, to microelectronics to spintronics to light harvesting for photovoltaics. Beyond their non-toxicity, low corrosiveness and low price, they exhibit a ...

EPFL2014

Theory of superconductivity in a three-orbital model of Sr2RuO4

Ronny Thomale, Yong Yang

In conventional and high transition temperature copper oxide and iron pnictide superconductors, the Cooper pairs all have even parity. As a rare exception, Sr2RuO4 is the first prime candidate for topological chiral p-wave superconductivity, which has time ...

IOP Publishing - EPL Association2013

Signatures of quantum criticality in the thermopower of Ba(Fe1-xCox)(2)As-2

László Forró, Richard Gaal, Stevan Arsenijevic

We demonstrate that the thermopower (S) can be used to probe the spin fluctuations (SFs) in proximity to the quantum critical point (QCP) in Fe-based superconductors. The sensitivity of S to the entropy of charge carriers allows us to observe an increase o ...

Amer Physical Soc2013