structural order parameter

1. structural order parameter electronic order parameter difference An atomic view of intertwined electronic and structural transitions: In/Si interface (I)Ward Plummer, University of Tennessee, DMR-0105232 In the strongly correlated electron materials, which include high Tc superconductors and colossal magnetoresistance materials, the structural phase transition is coupled with electronic, magnetic, or other transitions so tightly that it is difficult to study their correlation in detail. The interactive order parameters also result in inhomogeneity that usually controls the material properties. Scanning tunneling microscopy (STM) and spectroscopy (STS) are powerful tools with which the surface structure and electronic property simultaneously be investigated at atomic level. Readily accessible to STM and STS, the metal-adsorbed semiconductors surfaces that possess the strongly correlated nature are ideal playgrounds for testing the theory for the correlated electron systems. This work demonstrates how the structural (41) to (8 2) and electronic metal to pseudo-metal transitions are intertwined and interactive with each other in the In/Si interface. Top: The structural and electronic order parameters and their difference determined by the statistics from STM and STS. Bottom: Single phase metallic (41) at room temperature (right), pseudo-metallic (82) at 40 K (left), and multiple nanophases coexisted at 110 K (middle).PRL 95, 046102 & 116103 (2005)

2. An atomic view of intertwined electronic and structural transitions: In/Si interface (II) Ward Plummer, University of Tennessee, DMR-0105232The Broader Impact of this Work This work was conducted by Jiandong Guo, a post-doc at the university of Tennessee, and Geunseop Lee, a vistingg professor from Inha University, Korea. This investigation illustrates that easily fabricated metal-semiconductor systems with quasi one-dimensional characteristics can be used as a vehicle to study intertwined phase transition. These coupled phase transitions are indigenous to correlated electron systems. From left: Dr. Minghu Pan, Samuel Outten and Noppi Wadjaja (new students), Dr. Jiandong Guo, Dr. Jiandi Zhang (visiting scientists from a designated minority university FIU).