Dr. Igor Zutic

Photo of Professor Igor Zutic  

Professor, Ph.D. University of Minnesota (1998)

Office: 307A Fronczak Hall,   (716) 645-6599
Email: zigor@buffalo.edu
my CV for more info

Education

  Ph.D. -- Physics, University of Minnesota (1998)
B.S. -- Physics, University of Zagreb, Croatia (1992)

Research Interests

 
  • Spintronics and spin-polarized transport
  • High temperature and unconventional superconductivity
  • Ferromagnetic semiconductors
  • Theoretical nanoscience
  • Computational physics

  My interests in spintronics and spin-polarized transport span a wide range of topics and materials, from predicting novel ferromagnetic semiconductors to studying fundamental properties of high-temperature superconductors. I work on formulating a theoretical framework to predict and describe novel spin-dependent phenomena in solid-state systems as well as on proposing spintronic devices which could lead to applications that would be ineffective or infeasible with conventional electronics.

Spintronics is a multidisciplinary field whose central theme is the active manipulation of spin degrees of freedom in solid-state systems. Conventionally, the term spin stands for either the spin of a single electron, which can be detected by its magnetic moment, or the average spin of an ensemble of electrons, manifested by magnetization. The control of spin is then a control of either the population and the phase of the spin of an ensemble of particles, or a coherent spin manipulation of a single- or a few-spin system, important for quantum computing.

A comprehensive understanding of charge transport in electronic materials forms the foundation of conventional electronics. This well-established knowledge is based on the fact that the charge of a carrier is a robust property and that charge transport is usually effectively treated with the simple equations of semiclassical physics. In contrast, much less is known about the transport of a carrier's spin, an intrinsically quantum mechanical property which over the last decade has led to important applications based on magnetoresistive effects. Unlike its charge, a carrier's spin is not a robust property: the spin can be changed by applying a magnetic field, by the scattering of carriers, and by optical manipulation.

In a simple picture, it is helpful to distinguish carriers 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-polarized transport and involves both the transfer of spin and charge. This inequivalence between spin-up and spin-down carriers is responsible for magnetoresistive effects: changing the relative orientation of the magnetization in different parts of a device leads to changes in the electrical resistance. The resulting applications---such as magnetic read heads (the key component of computer hard drives) and magnetic random access memory (MRAM)---are nonvolatile: the magnetically encoded information can be preserved even without a supply of electric power.

With my collaborators I have recently examined some intriguing implications of incorporating spin-dependent properties and magnetism in semiconductor structures which go beyond magnetoresistive effects. For example, we have predicted the spin-voltaic effect, a spin-analog of the photo-voltaic effect, a spin capacitance, and a spin density amplification, as well as proposed a spin-polarized battery and a concept of magnetic bipolar transistor for spin-enhanced logic. However this is just the beginning and many important challenges remain to be understood.

Selected Publications

  1. Spin injection and detection in silicon, I. Zutic, J. Fabian, and S. C. Erwin, Phys. Rev. Lett. 97, 026602 (2006), cond-mat/0412580.
  2. Spintronics: Fundamentals and applications, I. Zutic, J. Fabian, and S. Das Sarma, Rev. Mod. Phys. 76 323 (2004), cond-mat/0405528.
  3. Tailoring ferromagnetic chalcopyrites, S. C. Erwin and I. Zutic, Nature Mater. 3, 410 (2004), cond-mat/040115.
  4. Spin-polarized transport in inhomogeneous magnetic semiconductors: theory of magnetic/ nonmagnetic p-n junctions, I. Zutic, J. Fabian, and S. Das Sarma, Phys. Rev. Lett. 88, 066603 (2002), cond-mat/0106085.
  5. Tunneling spectroscopy for ferromagnet/superconductor junctions, I. Zutic and O. T. Valls, Phys. Rev. B 61, 1555 (2000), cond-mat/9902080.