(American Physical Society, 2009) Churchill, Hugh Olen Hill; Kuemmeth, Ferdinand; Harlow, Jennifer W.; Bestwick, Andrew J.; Rashba, Emmanuel; Flensberg, Karsten; Stwertka, Carolyn H.; Taychatanapat, Thiti; Watson, Susan K.; Marcus, C
We use charge sensing of Pauli blockade (including spin and isospin) in a two-electron (^{13}C) nanotube double quantum dot to measure relaxation and dephasing times. The relaxation time (T_1) first decreases with a parallel magnetic field and then goes through a minimum in a field of (1.4 T). We attribute both results to the spin-orbit-modified electronic spectrum of carbon nanotubes, which at high field enhances relaxation due to bending-mode phonons. The inhomogeneous dephasing time (T_2^*) is consistent with previous data on hyperfine coupling strength in (^{13}C) nanotubes.
