Low-temperature scanning tunneling spectroscopy studies of a high-[Tc] superconductor

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7045273

Chang, A

Tunneling spectroscopy is a technique that can be used to measure the superconducting density of states, and can provide insight into the mechanism responsible for superconductivity. The scanning tunneling microscope (STM), invented and developed by Binnig and Rohrer in Zurich, is a powerful and proven tool for the study of the surface density of states. The spectrum of surface-state density is given by the measurement of conductance, dI/dV, versus tip-sample voltage. STM allows observation the surface topography Z(x,y), and also study of the energy spectroscopy, i.e., the electronic density of states of a high-T[sub c] superconductor, which is important to understand the microscopic mechanism responsible for superconductivity. The authors have used a low temperature scanning tunneling microscope (LTSTM) to study and map the electronic density of states in the superconducting phase of Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8-[sigma]](Bi-2212), and performed the mapping of the tunneling conductance G(V,x,y) with 5 [angstrom] resolution on cleaved ab-planes of Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8-[sigma]] crystals (90 K T[sub c]). The main contributions are the mapping of the tunneling conductance and superconducting energy gap, with an improved spatial resolution of 5 [angstrom], and the consequent discovery of evidence for an internal proximity effect in the layered superconductor Bi-2212.

• Research Organization: Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)
• OSTI ID: 7045273
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
CUPRATES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HIGH-TC SUPERCONDUCTORS
INTERMETALLIC COMPOUNDS
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTIVITY
SUPERCONDUCTORS
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TUNNEL EFFECT