That is basically correct, but both "/home/checkpoint.nc" and "/Desktop" would likely not work... Probably it should be more like /home/yourusername/Desktop/checkpoint.nc or just /home/yourusername/checkpoint.nc.
Well, the idea is correct. Your code is wrong. The checkpoint must be set on the DeviceLCAOCalculator - you cannot set an LCAOCalculator on a DeviceConfiguration anyway.