Changing electronic properties at oxide interfaces Charles Ahn , Yale University, DMR 1006256

1. Changing electronic properties at oxide interfaces Charles Ahn, Yale University, DMR 1006256 depletion When dissimilar materials come in contact with each other, structural interactions at interfaces can strongly affect the electronic properties. We have shown that dynamic structural distortions (phonons) in nano-scale devices can dominate electronic behavior at oxide interfaces. In transistor-like structures, we observe that phonons at an oxide interface lead to the development of sharp cusps in the electronic behavior (at ~100 K). In particular, we find that phonons in one oxide material (SrTiO3) can propagate across an atomic-scale interface to another oxide (LaSrMnO3), drastically changing the conductivity of the LaSrMnO3. The transistor-like structure allows us to study the size of the cusp as a function of how many electrons are at the interface. (In depletion, there are fewer electrons, and in accumulation, there are more electrons). accumulation A transistor-like field effect device (inset) is used to modulate the number of electrons in an LaSrMnO3 film, allowing one to determine the effect of phonons on the electronic properties of the LaSrMnO3 layer. A voltage is applied across the V+ and V- electrodes, and a current is measured between the I+ and I- electrodes. r is the inverse of the conductivity.

2. Growing materials for low power magneto-electric logic devicesCharles Ahn, Yale University, DMR 1006256 Heather Hawkes, an undergraduate Mechanical Engineering major, fabricates advanced multifunctional materials in the laboratory. Using tools specialized for the growth of materials for the modern electronics industry, Heather developed a process to fabricate high quality zinc oxide (ZnO) films, whose superior electro-mechanical properties can be coupled to magnetic materials to develop novel magneto-electric logic devices. Heather used a broad array of characterization techniques, including advanced microscopies, to characterize the materials properties of her ZnO films. Glue X-ray of ZnO Undergraduate Heather Hawkes grows thin layers of ZnO using advanced sputter deposition techniques.