The interplay of charge ordering with superconducting correlations in underdoped cuprates at high magnetic fields (H) is an open question, and even the value of the upper critical field has been the subject of a long-term debate. We combined three complementary transport techniques on underdoped La-214 cuprates with a “striped” charge order and a low H=0 transition temperature Tc0, which opens a much larger energy scale window to explore the vortex phases compared to previous studies. We determine the T-H phase diagram, directly detect the upper critical field, and probe deep into the normal state. Our results demonstrate a key role of disorder in the behavior of vortex matter as T®0. Furthermore, the agreement between our transport results in H and spectroscopic data in H=0 provides a unified perspective on the superconducting phase transition in underdoped cuprates. Most strikingly, however, within the vortex glass region we discover the emergence of an unanticipated, insulatinglike state, but with strong superconducting correlations. This novel state is consistent with the ordering of localized Cooper pairs within the quasi-1D stripes, but other possible scenarios will be also discussed. The presence of stripes, however, plays a crucial role in the freezing of Cooper pairs in this novel state. Our findings offer a qualitatively new test of theoretical proposals for dominant orders in the charge-ordered region of the pseudogap phase in cuprates.
This work was supported by NSF Grants No. DMR-1307075 and No. DMR-1707785, and the National High Magnetic Field Laboratory through the NSF Cooperative Agreement No. DMR-1157490 and the State of Florida.
Educational Background
1989 Ph.D., Physics, Brown University
1985 M.Sc., Physics, Brown University
1983 B.Sc., Physics, University of Belgrade, Yugoslavia
Professional Experience:
2014-present Senior Scientist (change of work title), NHMFL
2004-2013 Scholar/Scientist, NHMFL
2000-2004 Associate Scholar/Scientist, NHMFL
1997-2000 Assistant Scholar/Scientist, NHMFL
1995-1997 Visiting Scientist, NHMFL
1993-1997 Assistant Professor of Physics, City College of the City University of New York
April 1990-1993 Postdoctoral Research Associate, IBM T.J. Watson Research Center
1989-March 1990 Postdoctoral Research Associate, Brown University
Awards, Honors, and Service：
Outstanding Referee, American Physical Society (2017)
Research Professor, Department of Physics, Florida State University (2017)
Distinguished University Scholar, Florida State University (2013)
Fellow, American Physical Society (2012)