Magnetic quantum oscillations in YBa2Cu3O6.61 and YBa2Cu3O6.69 in fields of up to 85 T: patching the hole in the roof of the superconducting dome.
We measure magnetic quantum oscillations in the underdoped cuprates YBa2Cu3O6+x with x=0.61, 0.69, using fields of up to 85 T. The quantum-oscillation frequencies and effective masses obtained suggest that the Fermi energy in the cuprates has a maximum at hole doping p approximately 0.11-0.12. On either side, the effective mass may diverge, possibly due to phase transitions associated with the T=0 limit of the metal-insulator crossover (low-p side), and the postulated topological transition from small to large Fermi surface close to optimal doping (high p side).
Singleton
John
J
National High Magnetic Field Laboratory, Los Alamos National Laboratory, MS-E536, Los Alamos, New Mexico 87545, USA.
de la Cruz
Clarina
C
McDonald
R D
RD
Li
Shiliang
S
Altarawneh
Moaz
M
Goddard
Paul
P
Franke
Isabel
I
Rickel
Dwight
D
Mielke
C H
CH
Yao
Xin
X
Dai
Pengcheng
P