Excitonic Instability and Electric-Field-Induced Phase Transition Towards a Two-Dimensional Exciton Condensate.
Excitonic Instability and Electric-Field-Induced Phase Transition Towards a Two-Dimensional Exciton Condensate.
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DOI：
10.1103/physrevlett.77.900
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发表时间：
1996-03
影响因子：
8.6
通讯作者：
Yehuda Naveh;B. Laikhtman
中科院分区：
文献类型：
--
作者：
Yehuda Naveh;B. Laikhtman
我们提出了一个InAs-GaSb-为基础的系统中，其二维能隙的电场可调性意味着一个过渡到一个稳定的激子凝聚相。详细的计算表明，一个3 meV的BCS类间隙出现在一个二级相变与电场。我们发现这种转变是非常尖锐的，仅仅是由于交换相互作用，因此，激子结合能大大重整化，即使在小的凝聚密度。这种密度随着外场的增加而逐渐增加，从而使玻色-爱因斯坦到BCS交叉的直接探测成为可能。
We present an InAs-GaSb--based system in which the electric-field tunability of its 2D energy gap implies a transition towards a thermodynamically stable excitonic condensed phase. Detailed calculations show a 3 meV BCS-like gap appearing in a second-order phase transition with electric field. We find this transition to be very sharp, solely due to exchange interaction, and, so, the exciton binding energy is greatly renormalized even at small condensate densities. This density gradually increases with external field, thus enabling the direct probe of the Bose-Einstein to BCS crossover.