2024 New's Items

Considerations for extracting moiré-level strain from dark field intensities in transmission electron microscopy

Craig IM
Van Winkle M
Ophus C
Bediako DK
2024

Bragg interferometry (BI) is an imaging technique based on four-dimensional scanning transmission electron microscopy (4D-STEM) wherein the intensities of select overlapping Bragg disks are fit or more qualitatively analyzed in the context of simple trigonometric equations to determine local stacking order. In 4D-STEM based approaches, the collection of full diffraction patterns at each real-space position of the scanning probe allows the use of precise virtual apertures much smaller and more variable in shape than those used in conventional dark field imaging such that even buried...

Good plasmons in a bad metal

Ruta FL
Shao Y
Acharya S
Mu A
Jo NH
Ryu SH
Balatsky D
Pashov D
Analytis JG
Cava RJ
Shekhter A
McDonald RD
Zuo H
Lee H
Wu W
2024

Correlated materials may exhibit unusually high resistivity increasing linearly in temperature, breaking through the Mott-Ioffe-Regel bound, above which coherent quasiparticles are destroyed. The fate of collective charge excitations, or plasmons, in these systems is a subject of debate. Several studies suggest plasmons are overdamped while others detect unrenormalized plasmons. Here, we present direct optical images of low-loss hyperbolic plasmon polaritons (HPPs) in the correlated van der Waals metal MoOCl2. HPPs are plasmon-photon modes that waveguide through extremely anisotropic media...

Quantum decoherence by magnetic fluctuations in a candidate axion insulator

Saatjian R
Yamakawa K
Russell RS
Analytis JG
Harter JW
2024

In magnetic topological insulators, spontaneous time-reversal symmetry breaking by intrinsic magnetic order can open an energy gap in the topological surface spectrum. In the resulting state, exotic properties like axion electrodynamics, the quantum anomalous Hall effect, and other topological magnetoelectric responses are expected to emerge. A detailed understanding of the magnetic order and its coupling to the topological surface states is essential to harness and tune these properties. Here, we leverage near-resonant electric quadrupole optical second harmonic generation to probe...

Spontaneous Conducting Boundary Channels in 1T-TaS2

Devidas TR
Reichanadter JT
Haley SC
Sterenberg M
Moore JE
Neaton JB
Analytis JG
Kalisky B
Maniv E
2024

Materials that transition between metal and insulator, the two opposing states that distinguish all solids, are fascinating because they underlie many mysteries in the physics of the solid state. In 1T-TaS2, the metal-insulator transition is linked to a series of metastable states of a chiral charge density wave whose basic nature is still an open question. In this work, we show that pulses of current through these materials...

Collapse of susceptibility and nontrivial spin dynamics in the hyperhoneycomb magnet β − Li 2 IrO 3 under high pressure

Verrier A
Nagarajan V
Gendron L-T
Analytis JG
Quilliam JA
2024

We present high-pressure (2 GPa) 7Li nuclear magnetic resonance (NMR) measurements on single crystals of the hyperhoneycomb Kitaev magnet β-Li2IrO3. The spectra show evidence for a structural phase transition around 200 K and a coexistence of phases, consistent with the results of other measurement techniques. The NMR spectra and line shift measurements demonstrate a strong suppression of the local magnetic susceptibility at high pressure. However, the spin-lattice relaxation (1/T1) shows a clear power-law temperature dependence. This is inconsistent with a gapped singlet ground state of...

Phase control of spin waves in the van der Waals antiferromagnet NiPS3

Toyoda S
Kruppe J
Yamakawa K
Analytis JG
Orenstein J
2024

We demonstrate phase control of magnons in the van der Waals antiferromagnet NiPS3 using optical excitation by polarized light. The sign of the coherent precession of spin amplitude changes upon (i) reversing the helicity of a circularly polarized pump beam, or (ii) rotating the polarization of a linearly polarized pump by π/2. Because these two excitation pathways have comparable generation efficiency, the phase of spin precession can be continuously tuned from 0 to 2π by controlling the polarization state of the pump pulse. The ability to excite magnons with a desired phase has potential...

Multimodal Approach Reveals the Symmetry-Breaking Pathway to the Broken Helix in EuIn2⁢As2

Donoway E
Trevisan TV
Liebman-Peláez A
Day RP
Yamakawa K
Sun Y
Soh JR
Prabhakaran D
Boothroyd AT
Fernandes RM
Analytis JG
Moore JE
Orenstein J
Sunko V. A
2024

Understanding and manipulating emergent phases, which are themes at the forefront of quantum-materials research, rely on identifying their underlying symmetries. This general principle has been particularly prominent in materials with coupled electronic and magnetic degrees of freedom, in which magnetic order influences the electronic band structure and can lead to exotic topological effects. However, identifying symmetry of a magnetically ordered phase can pose a challenge, particularly in the presence of small domains. Here we introduce a multimodal approach for determining magnetic...

Coherent spin wave excitation with radio-frequency spin–orbit torque

Morrison N
Taghinejad H
Analytis JG
Ma EY
2024

Spin waves, collective perturbations of magnetic moments, are both fundamental probes for magnetic physics and promising candidates for energy-efficient signal processing and computation. Traditionally, coherent propagating spin waves have been generated by radio frequency (RF) inductive Oersted fields from current-carrying electrodes. An alternative mechanism, spin–orbit torque (SOT), offers more localized excitation through interfacial spin accumulation but has been mostly limited to DC to kHz frequencies. SOT driven by RF currents, with potentially enhanced pumping efficiency and unique...

Designed Spin‐Texture‐Lattice to Control Anisotropic Magnon Transport in Antiferromagnets

Meisenheimer P
Ramesh M
Husain S
Harris I
Park HW
Zhou S
Kavle P
Taghinejad H
Analytis JG
Nelson KA
Liu M
Spaldin NA
Rondinelli JM
Fiebig M
2024

Spin waves in magnetic materials are promising information carriers for future computing technologies due to their ultra-low energy dissipation and long coherence length. Antiferromagnets are strong candidate materials due, in part, to their stability to external fields and larger group velocities. Multiferroic antiferromagnets, such as BiFeO3 (BFO), have an additional degree of freedom stemming from magnetoelectric coupling, allowing for control of the magnetic structure, and thus spin waves, with the electric field. Unfortunately, spin-wave propagation in...

Non-volatile magnon transport in a single domain multiferroic

Husain S
Harris I
Meisenheimer P
Mantri S
Li X
Ramesh M
Behera P
Kavle P
Taghinejad H
Analytis JG
2024

Antiferromagnets have attracted significant attention in the field of magnonics, as promising candidates for ultralow-energy carriers for information transfer for future computing. The role of crystalline orientation distribution on magnon transport has received very little attention. In multiferroics such as BiFeO3 the coupling between antiferromagnetic and polar order imposes yet another boundary condition on spin transport. Thus, understanding the fundamentals of spin transport in such systems requires a single domain, a single crystal. We show that through Lanthanum (La)...