RESUMEN
Transport measurements can be used to determine the phase diagram of high temperature superconductors by detecting variations in temperature dependence of resistance in different regions of the phase diagram. While for bulk measurements several samples with varying chemical doping are used, we continuously vary carrier density in our ultra-thin two-dimensional Bi2Sr2CaCu2O[Formula: see text] device by electrostatic means and the space charge doping method. Here we concentrate on a low-disorder, high quality single unit cell thick sample. We establish the crossover to strange metal from the pseudogap and Fermi liquid phases in the normal state, close to the superconducting dome. By extrapolation we demarcate a critical doping region which is thought to correspond to a quantum phase transition at very low temperature.
RESUMEN
The phase diagram of hole-doped high critical temperature superconductors as a function of doping and temperature has been intensively studied with chemical variation of doping. Chemical doping can provoke structural changes and disorder, masking intrinsic effects. Alternatively, a field-effect transistor geometry with an electrostatically doped, ultra-thin sample can be used. However, to probe the phase diagram, carrier density modulation beyond 1014 cm-2 and transport measurements performed over a large temperature range are needed. Here we use the space charge doping method to measure transport characteristics from 330 K to low temperature. We extract parameters and characteristic temperatures over a large doping range and establish a comprehensive phase diagram for one-unit-cell-thick BSCCO-2212 as a function of doping, temperature and disorder.