  We present an entanglement concentration protocol for electrons based on
their spins and their charges. The combination of an electronic polarizing beam
splitter and a charge detector functions as a parity check device for two
electrons, with which the parties can reconstruct maximally entangled electron
pairs from those in a less-entanglement state nonlocally. This protocol has a
higher efficiency than those based on linear optics and it does not require the
parties to know accurately the information about the less-entanglement state,
which makes it more convenient in a practical application of solid quantum
computation and communication.
