导体通常指电阻率  < 10-4  · cm 的物质。金属和合金一般都是导体，如铝、金、钨、铜、镍铬 等。能带能隙很小或为 0 , 在室温下电子很容易获得能量而跃迁至导带而导电。-Usually refers to a conductor resistivity  < 10-4  cm material. Metals and alloys are generally conductors such as aluminum,