REDUCED DIMENSIONALITY IN SOLIDS

Physics 122

Christopher Levey

Extended (Bloch) states in an infinite periodic solid are the standard basis set for solid state physics. At another extreme, wavefunctions confined in a Coulomb potential are the basis for the electronic states of atomic physics. In this course we will investigate how our picture of solids changes in systems where excitations are best thought of as confined (narrow band) in one or more directions and extended (broad band) in the other directions. We will begin with a survey of the field, including fabrication techniques and an introduction to some of the differences between three dimensional (3D) solids and quasi zero-, one-, and two- dimensional systems. While artificially layered (2D) systems have been most extensively studied, we will also place an emphasis on molecular wires and artificial quantum wire systems (1D). We will consider both standard quantum confinement and the topological effects of reduced dimensionality.

Following this introduction (half the term) the seminar will be organized as a journal club, with members of the class presenting material from current, classic, and review articles. The level may range from that of Scientific American to Physical Review Letters. The subject of reduced dimensionality in solids is intentionally broad and covers many "hot topics" in condensed matter physics. I hope we can stimulate discussion on the similarities and differences in a broad range of effects while also concentrating on the subjects which most interest those present. In addition to the pursuing the rich literature on quantum wells and superlattices, we may discuss articles on the following: microcrystallite doped glasses (0D); arrays of quantum boxes (0D); quantum transport, Coulomb blockades and conductance fluctuations in mesoscopic electronic devices; organic semiconductors (1D); high Tc superconductors as natural 2D systems; anyon (fractional) statistics (as opposed to Fermi-Dirac or Bose-Einstein statistics) (2D); the quantum Hall effect (2D); and "fluxonic" (vs. electronic) circuits (2D). Both theory and experimental technique are appropriate.

Course obligations are (a) attendance, and (b) participation in the journal club. Class meeting times will be arranged (perhaps 2A). Our first meeting will be Thursday, September 26 at 2pm in 210 Wilder.

My hope is that the journal club may continue beyond the duration of this course (perhaps on a once a month basis).