| 1. |
- Goerzen, Moritz A., et al.
(author)
-
Lifetime of coexisting sub-10 nm zero-field skyrmions and antiskyrmions
- 2023
-
In: npj Quantum Materials. - : Nature Publishing Group. - 2397-4648. ; 8:1
-
Journal article (peer-reviewed)abstract
- Magnetic skyrmions have raised high hopes for future spintronic devices. For many applications, it would be of great advantage to have more than one metastable particle-like texture available. The coexistence of skyrmions and antiskyrmions has been proposed in inversion-symmetric magnets with exchange frustration. However, so far only model systems have been studied and the lifetime of coexisting metastable topological spin structures has not been obtained. Here, we predict that skyrmions and antiskyrmions with diameters below 10 nm can coexist at zero magnetic field in a Rh/Co bilayer on the Ir(111) surface—an experimentally feasible system. We show that the lifetimes of metastable skyrmions and antiskyrmions in the ferromagnetic ground state are above one hour for temperatures up to 75 and 48 K, respectively. The entropic contribution to the nucleation and annihilation rates differs for skyrmions and antiskyrmions. This opens the route to the thermally activated creation of coexisting skyrmions and antiskyrmions in frustrated magnets with Dzyaloshinskii–Moriya interaction.
|
|
| 2. |
- Siemann, Gesa R., et al.
(author)
-
Spin-orbit coupled spin-polarised hole gas at the CrSe2-terminated surface of AgCrSe2
- 2023
-
In: npj Quantum Materials. - 2397-4648. ; 8:1
-
Journal article (peer-reviewed)abstract
- In half-metallic systems, electronic conduction is mediated by a single spin species, offering enormous potential for spintronic devices. Here, using microscopic-area angle-resolved photoemission, we show that a spin-polarised two-dimensional hole gas is naturally realised in the polar magnetic semiconductor AgCrSe2 by an intrinsic self-doping at its CrSe2-terminated surface. Through comparison with first-principles calculations, we unveil a striking role of spin-orbit coupling for the surface hole gas, unlocked by both bulk and surface inversion symmetry breaking, suggesting routes for stabilising complex magnetic textures in the surface layer of AgCrSe2.
|
|
| 3. |
- von Arx, Karin, 1993, et al.
(author)
-
Fate of charge order in overdoped La-based cuprates
- 2023
-
In: NPJ QUANTUM MATERIALS. - : Springer Nature. - 2397-4648. ; 8:1
-
Journal article (peer-reviewed)abstract
- In high-temperature cuprate superconductors, stripe order refers broadly to a coupled spin and charge modulation with a commensuration of eight and four lattice units, respectively. How this stripe order evolves across optimal doping remains a controversial question. Here we present a systematic resonant inelastic x-ray scattering study of weak charge correlations in La2-xSrxCuO4 and La1.8-xEu0.2SrxCuO4. Ultra high energy resolution experiments demonstrate the importance of the separation of inelastic and elastic scattering processes. Long-range temperature-dependent stripe order is only found below optimal doping. At higher doping, short-range temperature-independent correlations are present up to the highest doping measured. This transformation is distinct from and preempts the pseudogap critical doping. We argue that the doping and temperature-independent short-range correlations originate from unresolved electron-phonon coupling that broadly peaks at the stripe ordering vector. In La2-xSrxCuO4, long-range static stripe order vanishes around optimal doping and we discuss both quantum critical and crossover scenarios.
|
|
