Scientific Highlights
μSR2020 conference update
The long delayed MuSR2020 conference will run from Monday 29th August to Friday 2nd September, 2022. An in-person meeting is planned, which will be held at the Science and Technology Campus, University of Parma. Invited speakers include Bruce Gaulin, Giacomo Ghiringhelli, Reizo Kato, Ioan Pop, Jorge Quintanilla, Roberta Sessoli, Martin Wilkening and Reiner Zorn
Spin-triplet superconductivity in Weyl nodal-line semimetals
Topological semimetals are three dimensional materials with symmetry-protected massless bulk excitations. As a special case, Weyl nodal-line semimetals are realized in materials having either no inversion or broken time-reversal symmetry and feature bulk nodal lines. The 111-family, including LaNiSi, LaPtSi and LaPtGe materials (all lacking inversion symmetry), belongs to this class. Here, by combining muon-spin rotation and relaxation with thermodynamic measurements, we find that these materials exhibit a fully- gapped superconducting ground state, while spontaneously breaking time-reversal symmetry at the superconducting transition.
First demonstration of tuning between the Kitaev and Ising limits in a honeycomb lattice
Recent observations of novel spin-orbit coupled states have generated interest in 4d/5d transition metal systems. A prime example is the Jeff = 1/2 state in iridate materials and α-RuCl that drives Kitaev interactions. Here, by tuning the competition between spin-orbit interaction (λSOC) and trigonal crystal field (ΔT), we restructure the spin-orbital wave functions into a previously unobserved μ=1/2 state that drives Ising interactions.
Optical Setup for a Piston-Cylinder Pressure Cell: A Two-Volume Approach
Measurement of the absolute value of the applied pressure in high-pressure muon and neutron experiments is a complicated task. It often requires the presence of a calibration material inside the sample volume, and could also cause additional time to obtain the response of the calibrant. Here we describe the use of optical calibrants for precise determination of the pressure value inside the piston-cylinder clamp cells.
New insight into unconventional superconductivity
Signatures for a novel electronic phase that enables charge to flow spontaneously in loops have been observed in a kagome superconductor. The findings are published today in Nature.
Muon spin spectroscopy
Muons are particles with a spin of 1⁄2 that can be implanted into a wide range of condensed matter materials to act as a local probe of the surrounding atomic environment. Measurement of the muon’s precession and relaxation provides an insight into how it interacts with its local environment. From this, unique information is obtained about the static and dynamic properties of the material of interest ...
SμS Call 2022/1 informations
The results of the evaluation of the SμS Call 2022/1 and the beam time schedule will be published mid of March 2022. Resume of HIPA user operation is scheduled to May 2nd, 2022.
Precision Measurement of the Lamb Shift in Muonium
We report a new measurement of the n=2 Lamb shift in Muonium. Our result of 1047.2(2.3)stat(1.1)syst MHz comprises an order of magnitude improvement upon the previous best measurement. This value matches ...
Signatures of Weyl Fermion Annihilation in a Correlated Kagome Magnet
The manipulation of topological states in quantum matter is an essential pursuit of fundamental physics and next-generation quantum technology. Here we report the magnetic manipulation of Weyl fermions in the kagome spin-orbit semimetal Co3Sn2S2, observed by high-resolution photoemission spectroscopy. We demonstrate the exchange collapse of spin-orbit-gapped ferromagnetic Weyl loops into paramagnetic Dirac loops under suppression of the magnetic order.