arXiv subjects

M Arnold

Publications and source records attributed to M Arnold.

2 recordsLinked to original sources

arXiv2026

Mechanical control of competing magnetic order in crystalline MnPtGa membranes

MnPtGa hosts competing magnetic states, including ferromagnetic, canted antiferromagnetic, and spin density wave (SDW) order in the centrosymmetric $P6_3/mmc$ structure, while a related inversion-broken structure supports chiral skyrmions. Controlling this competition motivates materials platforms that enable tunable strain and symmetry breaking, together with probes of SDW order compatible with ultrathin samples. Here, we demonstrate single crystalline MnPtGa membranes grown by molecular beam epitaxy on graphene/Ge(111) and released by mechanical exfoliation. X-ray and electron diffraction confirm high crystalline quality. SQUID magnetometry reveals a 140 K anomaly in the zero-field-cooled $dM/dT$ that persists after exfoliation, while time-resolved reflectivity shows a coincident peak in the electronic relaxation time consistent with a quasiparticle phonon bottleneck associated with a putative SDW gap. Intentional rippling suppresses the $\sim 140$ K magnetic anomaly, demonstrating mechanical control of the low-temperature state. These results establish MnPtGa membranes as a platform for detecting and strain-tuning competing magnetic orders.

cond-mat.mtrl-sci↗

arXiv2013

High energy photoelectron emission from gases using plasmonics enhanced near-fields

We study theoretically the photoelectron emission in noble gases using plasmonic enhanced near-fields. We demonstrate that these fields have a great potential to generate high energy electrons by direct mid-infrared laser pulses of the current femtosecond oscillator. Typically, these fields appear in the surroundings of plasmonic nanostructures, having different geometrical shape such as bow-ties, metallic waveguides, metal nanoparticles and nanotips, when illuminated by a short laser pulse. In here, we consider metal nanospheres, in which the spatial decay of the near-field of the isolated nanoparticle can be approximated by an exponential function according to recent attosecond streaking measurements. We establish that the strong nonhomogeneous character of the enhanced near-field plays an important role in the above threshold ionization (ATI) process and leads to a significant extension in the photoelectron spectra. In this work, we employ the time dependent Schrödinger equation in reduced dimensions to calculate the photoelectron emission of xenon atoms in such enhanced near-field. Our findings are supported by classical calculations.

physics.optics↗