Samarium Hexaboride have both property of conductor and insulator.

1. Http://www.zegmetal.com
Samarium Hexaboride: Both Conductor and Insulator
Recently, research team from University of Cambridge
found samarium hexaboride of fantasic electrical
characteristics, which positvely prove topological insulator
( close to rattan insulators), when low temperature,
surface of SmB6 present conductive characteristics of
metal property, but inner of material, it present
characteristics of insulator. This research prove an new
kind of conductive characteristics of materials, which
challenge people perceive of traditional metal and
insulating material.
The research group is leaded by professor Suchitra
Sebastian, who found special and difficult-
explaining materials, Samarium hexaboride, which is
good conductor at room temperature and it turn
topological insulator whose manner of inner electron is
complex and interaction is special.