Abstract
We successfully tuned an underdoped ultrathin YBa 2Cu 3O 7-x film into the overdoped regime by means of electrostatic doping using an ionic liquid as a dielectric material. This process proved to be reversible. Transport measurements showed a series of anomalous features compared to chemically doped bulk samples and a different two-step doping mechanism for electrostatic doping was revealed. The normal resistance increased with carrier concentration on the overdoped side and the high temperature (180 K) Hall number peaked at a doping level of p∼0.15. These anomalous behaviors suggest that there is an electronic phase transition in the Fermi surface around the optimal doping level.
Original language | English (US) |
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Article number | 067004 |
Journal | Physical review letters |
Volume | 108 |
Issue number | 6 |
DOIs | |
State | Published - Feb 10 2012 |