In a new paper in npj Quantum Materials we show how small rotations of the ruthenium oxide octahedra in the enigmatic superconductor Sr2RuO4 enable us to detect its van Hove singularity, which would otherwise be practically invisible for us due to its orbital character. Modelling of the quasiparticle interference shows excellent agreement with experiment once the rotation of the octahedra is accounted for, resulting in chiral scattering patterns around defects.
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Quasiparticle interference on a rock
Analogous to Magellan’s circumnavigation of the earth enabling him to deduce information about the shape of the earth in 3D from its surface, read our new paper in Nature Communications to find out how we can use 2D quasi-particle interference at the surface of a rock to infer information about its 3D electronic structure.
Measuring Exchange Interactions using Helium
Read our new paper in Physical Review Letters to find out how one can use helium to measure exchange interactions between a sample and the tip of a Scanning Tunneling Microscope. We show that helium becomes trapped in the tunneling junction, but can be ejected by the tunneling electrons enabling us to spatially map its binding energy. Alternative title could have been ‘how a helium leak enabled us to probe exchange interactions’.
Meet us in Cyberspace at the Virtual DPG Meeting
Meet members of the group and hear about our most recent results in the following talks and posters at the virtual meeting of the condensed matter section of the DPG (27 September – 1 October 2021, see here for a list of our contributions, note that times are CEST (UTC+2)):
- Christopher Trainer on Monday, 27.9., 10:30, talk MA 1.2: The effect of trapped Helium atoms on spin polarized tunneling in an STM tunnel junction
- Olivia Armitage on Tuesday, 28.9., 10:30, talk MA 4.2: Spin-polarised imaging and quasi-particle interference of the van-der-Waals ferromagnet Fe3GeTe2
- Izidor Benedičič on Tuesday, 28.9., 13:30, poster TT 9.27: Anisotropic metamagnetism in trilayer ruthenate Sr4Ru3O10
- Carolina Marques on Thursday, 30.9., 12:15, talk TT 19.5: Nematicity and checkerboard order in the surface layer of Sr2RuO4
In addition, Andreas Kreisel from University of Leipzig will talk about our joint work on Sr2RuO4 on Thursday, 30.9., 12:30, in talk TT 19.6 on Quasiparticle Interference of the van-Hove singularity in Sr2RuO4.
Our van-Hove singularities on the back cover of Advanced Materials
Our paper on magnetic-field tunable van-Hove singularities in Sr2RuO4 featured on the back cover of Advanced Materials. The image shows the structure of the van-Hove singularity and the two order parameters required to obtain it, nematicity and checkerboard charge order.
Read more in the original reference: Magnetic-Field Tunable Intertwined Checkerboard Charge Order and Nematicity in the Surface Layer of Sr2RuO4, 2021, 32, 2100593.
Cover image © Wiley-VCH GmbH. Reproduced with permission.
Can one do bulk measurements in an STM?
Do you think STM is only a surface-sensitive probe? Read Christopher’s new preprint where we show magnetostriction measurements done in our vector-field STM and use it to map out the phase diagram of CeSb2. An exciting way to directly link bulk properties to the surface electronic structure.
Händel’s Passacaglia and electron correlations
What has Händel’s Passacaglia to do with electron correlations? Find out more about the aesthetics of emergent phenomena from Carolina’s talk in the Nottingham Prize Competition at the Physical Electronics Conference 2021. Click 👍 if you like it!
New paper: Magnetic field-tunable checkerboard charge order and nematicity at the surface of Sr2RuO4
Our new paper on the surface layer of Sr2RuO4 has appeared in Advanced Materials (Early View). Check it out to see how checkerboard charge order and nematicity emerge at the surface of the enigmatic superconductor Sr2RuO4, a material that continues to surprise. Our work raises interesting questions as to what one can learn from the surface electronic structure about bulk instabilities of a material.
New paper: Strain-Stabilized order in FeTe
Our paper on strain-stabilized (π,π) order at the surface of FeTe has appeared in Nano Letters (here), showing how in samples under uniaxial strain a new surface phase emerges, showing (π,π) charge order with only short-ranged magnetic order instead of the usual (π,0) magnetic order of FeTe.
Meet us at the APS March Meeting
Meet us at the APS march meeting and learn more about our research. You can see members of the group and our research at the following contributions:
- Wednesday, March 17, 2021, 10:48–11:00: Soumendra Panja: “Tuning the ground state of iron based superconductors by uniaxial strain”
- Wednesday, March 17, 2021, 16:36-16:48: Chi-Ming Yim: “Strain-tuning emergent phases in FeTe between (π,0) and (π,π) order”
- Thursday, March 18, 2021, 8:00–8:12: Carolina Marques: “Checkerboard charge order, nematicity and magnetic-field tuning of a van Hove singularity in the surface layer of Sr2RuO4“
- Thursday, March 18, 2021, 12:06–12:42: Luke Rhodes: “Understanding the nematic electronic structure of FeSe and its impact on the superconducting state”