Near-Room Temperature Studies of the Pseudogap Phase of Underdoped Bi-2212

Most scanning tunneling microscopy (STM) studies on significantly underdoped samples of the high-temperature superconductor Bi-2212 have been conducted at low temperatures where the pseudogap state coexists with superconductivity. The pseudogap phase transition for these materials occurs at relatively high temperatures, $T^* > 300\, K$, a region of the phase diagram which is largely unexplored by STM. Here we present our temperature-dependent STM measurements of the pseudogap state of underdoped Bi-2212 in the vicinity of $T^*$.