Linear Interplay Between Raman Shift and Laser Irradiation in Photothermal-Strained Monoclinic Vanadium Dioxide.

Vanadium dioxide as a strongly correlated electron material undergoes metal-insulator phase transitions and ferroelastic domain switching which highly couple to local strain distribution. Understanding the mechanisms and achieving the modulations require precise and high-resolution characterization of strain in vanadium dioxide. Micro-Raman spectroscopy is widely used to nondestructively characterize the strain on the surface of materials.

Microdynamic Study of Spin-Lattice Coupling Effects on Skyrmion Transport.

Skyrmion transport fundamentally determines the speed, energy consumption, and functionality of skyrmion-based spintronic devices, attracting considerable attention. Recent experimental studies found there is a migration barrier for the thermal activated transport of a skyrmion, which is speculated to be induced by the pinning effects of crystalline defects. In this Letter, we propose an alternative source of migration barrier for skyrmion transport, i.

Ferromagnetic effects on helium-vacancy complex formation in BCC Fe.

The substitution of helium atom inside BCC Fe results in (1) lattice distortion, (2) the resonance phonon modes, and (3) the scattering center, enhancing the anharmonicity of phonon and magnon. The ferromagnetic effects are analyzed by comparing results in the ferromagnetic and non-magnetic systems using spin-lattice dynamics simulations based on quantum fluctuation dissipation relation. The ferromagnetic effects are subtracted into static and dynamic contributions, where the former is found to be dominant.

Quantum statistical effects in the mass transport of interstitial solutes in a crystalline solid.

The impact of quantum statistics on the many-body dynamics of a crystalline solid at finite temperatures containing an interstitial solute atom (ISA) is investigated. The Mori-Zwanzig theory allows the many-body dynamics of the crystal to be formulated and solved analytically within a pseudo-one-particle approach using the Langevin equation with a quantum fluctuation-dissipation relation (FDR) based on the Debye model. At the same time, the many-body dynamics is also directly solved numerically via the molecular dynamics approach with a Langevin heat bath based on the quantum FDR.

Quantum statistics and anharmonicity in the thermodynamics of spin waves in ferromagnetic metals.

The average energy needed to create a magnon is high in ferromagnetic metals due to the high-strength spin stiffness, which results in strong quantization effects that could be important even at thousands of degrees. To take into account quantum statistics at such high temperatures, the associated effects of anharmonicity of the spin vibrations must be taken into account. In addition to the complex nature of such effects, anharmonicity also affects the occupation of the density of state of the vibration states in the context of quantum statistics.