Tafti lab is an interdisciplinary research group that integrates knowledge and expertise from physics, material science, and chemistry to search for new functional materials, the basis of our technological world. Our program brings together scientists from different fields to collaborate with and learn from each other in an exciting and friendly research environment. Our students have the opportunity to interact with experts from various fields and to take courses from different departments. We hope to educate a new generation of scientists capable of thinking outside the box, performing interdisciplinary research, becoming independent thinkers, and appreciating teamwork.
To guide our search for new materials, we use in-depth knowledge of quantum physics and quantum chemistry. We use Density Functional Theory to make an educated guess at interesting atomic combinations. Using an array of synthesis techniques, we combine elements into complex compounds and look for emergent phenomena. Emergence is a property of a complex system that is absent in its constituents. For example, neither Hydrogen (H) nor Oxygen (O) wet, but water (H2O) does. Our favorite emergent phenomena in solid state materials include frustrated magnetism, high temperature superconductivity, spin liquid, magnetoresistance, and thermoelectric effects.
Once we make a new material, we determine its structure by X-ray diffraction technique. Solid state systems form complex structures with various symmetries. X-ray diffraction experiments allow us to determine the set of symmetries inherent in a particular specimen. A detailed knowledge of crystallography is required to solve complex structures based on symmetry considerations.
Having made a new compound and having solved its structure, we embark on careful physics experiments to find out the interesting electrical, thermal, and magnetic properties of our material. We are equipped with a diverse array of physics experiments including most transport coefficients (resistivity, Hall, Seebeck, Nernst, and thermal codncutivity), magnetization (AC and DC susceptibiltity), and heat capacity. We can study materials at very low temperatures where thermal fluctuations freeze and give way to quantum effects.
To go one step further, we tune the behavior of electrons in solids by exposing them to intense magnetic fields and extreme pressures. High pressure experiments are complementary to material synthesis. When a structure goes under pressure, the interaction between atoms change due to their changing relative distances leading to unexpected phenomena. For example you may pressurize a magnetic material and replace magnetism with superconductivity. Our group has the expertise for ultrahigh pressure experiments with diamond anvil cells, a challenging but rewarding experiment. Another way of tuning materials is by subjecting them to intense magnetic fields. For example, certain metals could be tuned to show insulating behavior once in a large magnetic field. We travel to international high magnetic field laboratories for these experiments.