309 Fronczak Hall
Spintronics and spin-dependent phenomena, Semiconductor nanostructures, Van der Waals heterostructures, Magnetism, Unconventional superconductivity, Theoretical nanoscience, Computational physics
I am interested in spintronics and spin-dependent phenomena that span a wide range of topics and materials, from predicting novel, strongly-correlated states in semiconductor nanostructures to studying fundamental properties of unconventional superconductors. I work on formulating a theoretical framework to predict and describe unexplored spin-dependent phenomena in solid-state systems, as well as on proposing spintronic devices that could lead to applications that would be ineffective or not feasible with conventional electronics, from spin lasers and spin transistors to topologically-protected quantum computing. Many of our predictions are experimentally verified and we closely collaborate with a number of experimental groups. The techniques we use range from analytical methods, rate equations, and mean-field models, to first-principles studies, Monte Carlo simulations, and many-body calculations.
In a simple picture, it is helpful to distinguish carriers (electrons and holes) as having "spin up'' and "spin down'' (determined,for example, by the direction of applied magnetic field or by the direction of magnetization in a ferromagnetic material). In magnetic materials, the properties of spin-up and spin-down carriers are generally inequivalent. For example, the two types of carriers have different densities of states, conductivities, electric currents, and group velocities. Consequently, the transport of such carriers is referred to as spin-dependent transport and involves both the transfer of spin and charge. This inequivalence between spin-up and spin-down carriers is responsible for the discovery of large resistance changes by an applied magnetic field(giant magnetoresistance) that has enabled a thousand-fold increase in the information storage density of computer hard drives in a decade and was recognized by the 2007 Nobel Prize in Physics. However, this may only be the tip of the iceberg. A versatile control of spin and magnetism in a wide class of materials and their nanostructures, which we are studying, could also have much broader impact leading to a new generation of multi-functional devices that seamlessly integrate memory and logic for low-power/high-speed operation. This is just the beginning and many important challenges remain to be understood.
Various topics we study involve undergraduate students who for their research and publications have received many prestigious awards, including Goldwater Scholarship, National Science Foundation Graduate Fellowship, and National Defense Science & Engineering Graduate Fellowship.
For a complete list of publications, please visit Cornell University Research Library.