Grant: Discovery Grants Program - Individual

In the last twenty years, electronic devices such as cell phones, personal computers, smart TV and guidance systems for transportation, have changed our lives. All these devices rely on a deep understanding of the properties of pure silicon and of the effects of adding small amounts of other atoms, such as phosphorus. A few other materials are important, gallium arsenide being another one. The mathematical methods that have unraveled the behavior of these materials were born with quantum mechanics almost a century ago. It was sufficient to solve simple quantum mechanical models to understand the properties of these materials. This was done more than 50 years ago, but a lot of engineering was then necessary to reach the point where electronic devices would permeate our lives. Today, more complex materials containing oxygen, copper, rare earths and almost all other kinds of atoms are becoming essential for new technologies. Examples of useful properties of these complex materials include strong magnets, devices that can extract electricity from heat and superconductors. Superconductors carry electricity without losses, allow sensitive measurements of weak magnetic fields, are used in medical imaging and in devices for quantum computers. My group works on these kinds of materials, in particular superconductors and magnetic materials. In these so-called quantum materials, the physics is controlled by the collective, highly quantum mechanical behavior of electrons. All known materials that become superconductors must be refrigerated at very low temperature or maintained at very high pressure. Finding a material that becomes superconductor at ambient conditions of temperature and pressure is one of the ultimate challenges in this field. To reach this goal, science-driven research is necessary because the traditional mathematical methods that have allowed us to understand silicon do not work for these new classes of materials. We develop new mathematical methods and computer algorithms that solve the quantum mechanical equations describing quantum materials. We use these methods to solve models that explain existing experiments and predict the results of new ones. For example, we found out recently that we can predict which property is important to raise the temperature where a material becomes superconducting. These methods need to be refined to be able to make predictions of physical properties based on first principles, or on more realistic models. Our work is important for experimentalists, for chemists and for material scientists who make materials and study them. It is important for the general public, who will benefit from our scientific advances thanks to the work of engineers who will turn these materials into useful devices. The problems that we work on are an ideal setting to train students so that they learn how to solve difficult problems. This is our main and most important immediate contribution to society.