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.

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

Image: Chi Ming Yim

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:

Meet us at the APS March Meeting

Hadn’t it been cancelled you could have met us at the APS march meeting in Denver and learned more about our research. Members of the group had the following contributions: