论文标题
2D石墨烯音调晶体中的机械触发带隙闭合
Mechanically-tunable bandgap closing in 2D graphene phononic crystals
论文作者
论文摘要
我们提出了一个可调的语音晶体，该晶体经历了从机械绝缘到机械传播（金属）的相过渡。具体而言，在我们在双轴张力下的语音晶格的模拟中（$σ_{xx} =σ_{yy} $ = 0.01 n $ /$ m），我们在平面外声子中找到一个在48.8-56.4 mHz范围内的平面声音频段，我们可以通过增加Tensime nimiaialiaxial（$ niaialiaxial）的范围（我们可以增加）（$ 56.4 MHz） σ_{yy} $）至1.7。为了操纵张力分布，我们设计了一个有限尺寸的逼真的设备，其中$σ_{xx} /σ_{yy} $是通过将栅极电压施加到由悬浮石墨烯制成的音调晶体中来调谐的。我们表明，可以通过声音传输测量值探测相变，并且即使在逼真的设备中存在包含表面污染物和随机张力变化之后，语音带隙仍存在。所提出的系统充当了$ 10^5 $（100 dB抑制）的声子的晶体管，因此是声子逻辑应用程序的有价值的扩展。此外，这种对金属绝缘体过渡（MMIT）的机械类似物允许在机械实体（例如机械量子位）之间进行可调耦合。
We present a tunable phononic crystal which undergoes a phase transition from mechanically insulating to mechanically transmissive (metallic). Specifically, in our simulations for a phononic lattice under biaxial tension ($σ_{xx} =σ_{yy}$ = 0.01 N$/$m), we find a bandgap for out-of-plane phonons in the range of 48.8 - 56.4 MHz, which we can close by increasing the degree of tension uniaxiality ($σ_{xx} / σ_{yy}$) to 1.7. To manipulate the tension distribution, we design a realistic device of finite size, where $σ_{xx} / σ_{yy}$ is tuned by applying a gate voltage to a phononic crystal made from suspended graphene. We show that the phase transition can be probed via acoustic transmission measurements and that the phononic bandgap persists even after the inclusion surface contaminants and random tension variations present in realistic devices. The proposed system acts as a transistor for phonons with an on/off ratio of $10^5$ (100 dB suppression) and is thus a valuable extension for phonon logic applications. In addition, this mechanical analogue to a metal-insulator transition (mMIT) allows tunable coupling between mechanical entities (e.g. mechanical qubits).
