NMR Evidence for a Magnetic Soliton Lattice in the High-Field Phase of CuGeO

Observation of charge density wave solitons in overlapping tunnel junctions

We report on direct observation of microscopic solitons in single electronic processes of the coherent interlayer tunneling in charge density waves. Special nanoscale devices were fabricated from the chain compound using focused ion beams. The spectra were drastically refined by working at high (up to 27 T) magnetic fields. Internal quantum tunneling of electrons can go through solitons that are energetically more favorable quantum particles than electrons. In addition to the interband tunneling across the gap 2Delta, we observe a clear peak at the intermediate voltage approximately 2Delta/3, which we associate with the creation of microscopic solitons, the energy of which must be 2Delta/pi. These solitons might correspond to the long sought special quasiparticle--the spinon.