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Designing landscapes of correlations and topology: a strain-gradient approach

Ouvert au grand public Colloque / Congrès / Forum
21.11.2018 17:15 - 21.10.2018 18:15

The phase diagrams of strongly correlated materials are typically rich and complex, reflecting the competition of various ordered phases for states at the Fermi level. We currently explore new approaches to fabricate single crystal devices in which multiple of such phases coexist in different locations of a device. A spatial modulation of the correlation strength can be achieved by controlling a strong strain gradient in the sample. Using Focused-Ion-Beam machining, we fabricate micrometer-sized single crystal devices from quantum materials and subject them both to passive strain fields via thermal contraction as well as actively driving them in a MEMS setting. This allows the generation of strong yet well-controlled strain gradients. Two concrete recent examples will be discussed: In the heavy-fermion superconductor CeIrIn5, the hybridization strength of the 4f1-electron with the conduction band can be tuned in real space through strain gradient fields. In the Dirac semi-metal Cd3As2, strain gradients move (and potentially merge) the nodes, leading to the emergence of “pseudo-magnetic” fields which influence the quasiparticles akin to Landau quantization in real magnetic fields. I will present the physical questions that become tangible when strong strain gradients can be controlled, our experimental and technical approaches to generate them, as well as our recent results.

Quand? 21.11.2018 17:15    -    21.10.2018 18:15
Où? PER 08 0.51 bâtiment de Physique
Chemin du Musée 3
1700 Fribourg
Intervenants Prof. Philipp Moll
École Polytechnique Fédérale de Lausanne (EPFL)
Contact Prof. Christian Bernhard
Chemin du Musée 3
1700 Fribourg
026 300 90 70
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