TY - JOUR
T1 - Dynamical instability of a driven-dissipative electron-hole condensate in the BCS-BEC crossover region
AU - Hanai, Ryo
AU - Littlewood, Peter B.
AU - Ohashi, Yoji
N1 - Funding Information:
We thank M. Yamaguchi, D. Inotani, H. Tajima, and A. Edelman for discussions. This work was supported by the KiPAS project at Keio University. R.H. was supported by Grant-in-Aid for JSPS fellows (Grant No. 15J02513). Y.O. was supported by Grants-in-Aid for Scientific Research from MEXT and JSPS in Japan (Grants No. JP15K00178, No. JP15H00840, and No. JP16K05503). Work at Argonne National Laboratory is supported by the US Department of Energy, BES-MSE, under Contract No. DE-AC02-06CH11357.
Publisher Copyright:
© 2017 American Physical Society.
PY - 2017/9/28
Y1 - 2017/9/28
N2 - We present a stability analysis on a driven-dissipative electron-hole condensate in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover region. Extending the combined BCS-Leggett theory with the generalized random phase approximation to the nonequilibrium case by employing the Keldysh formalism, we show that the pumping and decay of carriers causes a depairing effect on excitons. This phenomenon gives rise to an attractive interaction between excitons in the BEC regime, as well as a supercurrent that anomalously flows antiparallel to θ(r) [where θ(r) is the phase of the condensate] in the BCS regime, both leading to dynamical instabilities of an exciton BEC. Our results suggest that a substantial region of the exciton-BEC phase in the phase diagram (in terms of the interaction strength and the decay rate) is unstable.
AB - We present a stability analysis on a driven-dissipative electron-hole condensate in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover region. Extending the combined BCS-Leggett theory with the generalized random phase approximation to the nonequilibrium case by employing the Keldysh formalism, we show that the pumping and decay of carriers causes a depairing effect on excitons. This phenomenon gives rise to an attractive interaction between excitons in the BEC regime, as well as a supercurrent that anomalously flows antiparallel to θ(r) [where θ(r) is the phase of the condensate] in the BCS regime, both leading to dynamical instabilities of an exciton BEC. Our results suggest that a substantial region of the exciton-BEC phase in the phase diagram (in terms of the interaction strength and the decay rate) is unstable.
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U2 - 10.1103/PhysRevB.96.125206
DO - 10.1103/PhysRevB.96.125206
M3 - Article
AN - SCOPUS:85030173277
SN - 2469-9950
VL - 96
JO - Physical Review B
JF - Physical Review B
IS - 12
M1 - 125206
ER -