Electron screening and excitonic condensation in double-layer graphene systems

被引:120
作者
Kharitonov, Maxim Yu. [1 ]
Efetov, Konstantin B. [2 ]
机构
[1] Ruhr Univ Bochum, D-44801 Bochum, Germany
[2] LD Landau Theoret Phys Inst, Moscow 119334, Russia
来源
PHYSICAL REVIEW B | 2008年 / 78卷 / 24期
关键词
carbon; excitons; nanostructured materials;
D O I
10.1103/PhysRevB.78.241401
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We theoretically investigate the possibility of excitonic condensation in a system of two graphene monolayers separated by an insulator in which electrons and holes in the layers are induced by external gates. In contrast to the recent studies of this system, we take into account the screening of the interlayer Coulomb interaction by the carriers in the layers, and this drastically changes the result. Due to a large number of electron species in the system (two projections of spin, two valleys, and two layers) and to the suppression of backscattering in graphene, the maximum possible strength of the screened Coulomb interaction appears to be quite small, making the weak-coupling treatment applicable. We calculate the mean-field transition temperature for a clean system and demonstrate that its highest possible value T-c(max)similar to 10(-7)epsilon(F)less than or similar to 1 mK is extremely small (epsilon(F) is the Fermi energy). In addition, any sufficiently short-range disorder with the scattering time tau less than or similar to h/T-c(max) would suppress the condensate completely. Our findings render experimental observation of excitonic condensation in the above setup improbable even at very low temperatures.
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页数:4
相关论文
共 25 条
[1]   Spontaneous symmetry breaking in graphene subjected to an in-plane magnetic field [J].
Aleiner, I. L. ;
Kharzeev, D. E. ;
Tsvelik, A. M. .
PHYSICAL REVIEW B, 2007, 76 (19)
[2]   Direct and indirect excitons in coupled GaAs/Al0.30Ga0.70As double quantum wells separated by AlAs barriers [J].
Bayer, M ;
Timofeev, VB ;
Faller, F ;
Gutbrod, T ;
Forchel, A .
PHYSICAL REVIEW B, 1996, 54 (12) :8799-8808
[3]  
BISTRITZER R, UNPUB
[4]   CONDENSATION OF INDIRECT EXCITONS IN COUPLED ALAS/GAAS QUANTUM-WELLS [J].
BUTOV, LV ;
ZRENNER, A ;
ABSTREITER, G ;
BOHM, G ;
WEIMANN, G .
PHYSICAL REVIEW LETTERS, 1994, 73 (02) :304-307
[5]   Bose-Einstein condensation of excitons in bilayer electron systems [J].
Eisenstein, JP ;
MacDonald, AH .
NATURE, 2004, 432 (7018) :691-694
[6]   Graphene via large N:: A renormalization group study [J].
Foster, Matthew S. ;
Aleiner, Igor L. .
PHYSICAL REVIEW B, 2008, 77 (19)
[7]   Magnetic field driven metal-insulator phase transition in planar systems [J].
Gorbar, EV ;
Gusynin, VP ;
Miransky, VA ;
Shovkovy, IA .
PHYSICAL REVIEW B, 2002, 66 (04) :451081-4510822
[8]  
KELDYSH LV, 1965, FIZ TVERD TELA+, V6, P2219
[9]   Magnetic-field-induced insulating behavior in highly oriented pyrolitic graphite [J].
Khveshchenko, DV .
PHYSICAL REVIEW LETTERS, 2001, 87 (20) :206401-1
[10]  
KHVESHCHENKO V, 2001, PHYS REV LETT, V87, DOI DOI 10.1103/PHYSREVLETT.87.246802