Two-dimensional, or 2D, materials are attracting considerable attention as a testbed for new physics and as candidates for applications in flexible nanoscale high-speed optoelectronics, solar energy conversion, and chemical sensing. Most unique properties of 2D materials stem from their highly anisotropic optical and electronic properties. Terahertz (THz) spectroscopy provides access to those properties with ultra-high time resolution and without the complications of electrical contacts.
Finding new ways for fast and efficient processing and transfer of data is one the most challenging tasks nowadays. Elementary spin excitations - magnons (spin wave quanta) - open up a very promising direction of high-speed and low-power information processing . Magnons are bosons, and thus they are able to form spontaneously a spatially extended, coherent ground state, a Bose-Einstein condensate (BEC), which can be established independently of the magnon excitation mechanism even at room temperature.
Localized magnetic configurations such as magnetic vortices and magnetic droplet solitons are great subjects for applications and fundamental understanding of spin dynamics since they can be controlled with external fields, electrical currents, and microwave excitations. Magnetic vortices are the ground state of certain micropatterned structures, whereas magnetic droplet solitons are created in an extended magnetic thin film by local excitation of spin waves. However, damping works against the formation of stable magnetic droplet solitons, and their stability is more challenging.
Much of our understanding of the biological mechanisms that underlie cellular functions, such as migration, differentiation and force sensing has been garnered from studying cells cultured on two-dimensional (2D) substrates. In the recent years there has been intense interest and effort to understand cell mechanics in three-dimensional (3D) cultures, which more closely resemble the in vivo microenvironment. However, a major challenge unique to 3D settings is the dynamic feedback between cells and their surroundings.
In this talk, we summarize the formalism we have developed to model heat transport in crystalline solids from first-principles density functional theory. We will illustrate the success of this approach by the results obtained for PbTe. In the second part, we will discuss the possibility of using 2D layered materials for converting heat to electricity in a solid-state thermionic device.
One of the principal advantages of thermoelelectric devices is their ability to convert heat into electricity and vice versa without any moving parts. Thermoelectric power generation is based on the Seebeck effect, where a voltage is induced when a semiconductor is under temperature gradient. In last two decades, a great effort has been made to enhance the range of high-performance thermoelectric materials for industrial applications [1-3].