1 / 2

Insert Figure 1 approximately here.

Study of the Fermi Surface of Bismuth Nanowires Tito E. Huber, Howard University, DMR 0506842. Bismuth nanowires or bismuth nanotubes?

aderes
Download Presentation

Insert Figure 1 approximately here.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Study of the Fermi Surface of Bismuth NanowiresTito E. Huber, Howard University, DMR 0506842 Bismuth nanowires or bismuth nanotubes? -Bismuth nanowires are a vehicle for the study of size-dependent electronic transport phenomena. While quantum size effects are predicted and expected, experiments that demonstrate quantum size effects in transport are scarce. -We have investigated the electrical transport properties of single-crystal individual nanowires with diameters in the 50 to 100-nm range. An oscillatory dependence of the resistance on the Aharonov-Bohm phase of the magnetic flux threading the wire is observed that can be interpreted by considering that the nanowire surface is more conducting than the core. Surface states (SurfS), believed to be due to Rashba spin- orbit coupling, have been observed in Bi surfaces using angle resolved photoemission spectroscopy and Shubnikov-de Haas spectroscopy of very small diameter Bi nanowires (Appl. Phys. Lett. 84 1326 (2004)). We believe that in our recent experiments, SurfS satisfy the quantum interference conditions, and are (simultaneously) orbital states around the nanowire and one-dimensional channels along the nanowire. -Figure: (top) shows the orbital states energy. The oscillations are due to the 1D peaks of the density of states when the orbital energy is at the Fermi level. (middle)The conductivity of the nanotube is linear with the number of 1D channels at high magnetic fields due to 1D channels added for increasing B. (bottom) Magnetoconductivity showing the oscillations associated with the peaks of the DOS. Insert Figure 1 approximately here.

  2. Study of the Fermi Surface of Bismuth NanowiresTito E. Huber, Howard University, DMR-0506842 Education: At Howard: One postdoc (O Aluko) that is now in the faculty of Michigan Tech, one undergraduate (P. Jones) that graduated in Spring’07 and is in Graduate School, U. New Hampshire, and two undergraduates that graduate in Spring’08 (T. Adunfa and A. Ajibola). At Boston College, undergrad J. Riley and graduate student R. Johnson. Other significant educational activity was mentoring of S. Abd-Al-Jabbar, College of Science for Woman, Baghdad, Irak; we collaborated in her thesis work ( Fabrication of Bi Filaments using electrophoresis). Impact: Our project aims to enable higher efficiency in the use of fossil fuels. A fraction of this energy is exhausted as heat. Potentially, this wasted energy (value zero) can be converted to electric power using solid state thermoelectric converters. However, market analysis show that this is feasible only if the conversion efficiency is increased by factor-two from the current value. Several approaches are being investigated to achieve this improvement. One-dimensional thermoelectrics are expected to have very high efficiencies (M.Dresselhaus, Physical Review (1993)). Our approach is to explore the fabrication methods and conditions necessary for demonstrating one-dimensional transport behavior in bismuth, that is one of the best known traditional thermoelectrics.

More Related