黑洞量子隧穿过程的时间

讨论了弯曲时空中黑洞量子隧穿的时间.在假定了黑洞量子隧穿是一个瞬时过程的情况下,通过利用WKB法得出了有静止质量粒子的量子隧穿辐射谱.该辐射谱表明对于在黑洞视界处有静止质量粒子的出射也满足量子力学中的幺正性原理,支持Parikh-Wilczek的结论.结果的合理性表明,在黑洞视界处的量子隧穿过程可以看成是一个瞬时过程.     

量子隧穿中的等效势垒

本文给出等效垫垒的概念及性质，利用等效势垒的性质可以使量子遂穿中的有关问题更容易解决。     

结构和磁场对三势垒结构中共振隧穿时间的影响

为了理解在三势垒结构中准束缚能级Ez和隧穿寿命对磁场的依赖性,采用传输矩阵的方法研究了在三势垒结构中的共振隧穿过程。分别研究了在三势垒结构中的透射几率特征和隧穿寿命。结果表明:随着中间势垒厚度L的增加,第一准束缚能级E1z增加,而第二准束缚能级E2z却减小。随着磁场强度B和朗道量子数n的增加,与第一和第二准束缚能级(E1z,E2z)对应的寿命τ缩短。对于B=15和n=15的情况,L对τ的影响很小。     

隧穿谱的研究进展

隧穿谱适宜于研究表面和界面的物理化学性质．它具有灵敏度高、谱范围宽和不受光学跃迁那样的选择定则限制等优点．本文介绍了隧穿谱的测量原理及其在探测分子的振动跃迁、电子跃迁，测量超导能隙和研究生物辐射损伤等方面的应用．对扫描隧穿显微镜（ＳＴＭ）的针尖－平面电极构成的隧道结构和金属－氧化物－金属平面型隧道结构作了比较，分析了它们用于测量隧穿谱时的优缺点，ＳＴＭ将促进隧穿谱研究的进一步发展．     

冷原子穿越激光束的量子隧穿时间

原子通过激光冷却技术能够被制备在低温状态，这时冷原子云会展现出量子力学的波动性.研究了一束冷原子入射到一个蓝失谐的激光束上所表现出的量子力学隧穿效应.蓝失谐的激光束相对于冷原子而言等效于一个量子力学势垒.根据二能级模型，在理论上分析了具有内部结构的原子矢量物质波穿过激光束的量子力学反射与透射，特别是对原子穿越激光束所需的时间——量子隧穿时间进行了详细的研究.量子力学波动性使得冷原子穿越一个激光束时明显地展现出与经典粒子(热原子)不同的结果. 关键词： 冷原子 原子光学 量子隧穿     

微波作用下有直接隧穿量子点系统中的泵流特性

利用演化算符的方法,研究了量子点体系中的电流以及自旋流,该体系中量子点和左右磁性电极耦合并且受到微波作用,且两电极之间有直接隧穿,得到了体系电流的解析表达式.发现对于无直接隧穿和零偏压情况,无论对称结构还是非对称结构,电流和自旋流总为零.对于直接隧穿和零偏压情况,对于两边为非对称结构,微波场辐射在量子点上可以导致自旋流而非零的总电流,给出了平行和反平行磁构型下的结果并进行了讨论;对于两边为对称结构结构,平行磁构型下,量子点上加微波场时自旋流和总电流均为零;在反平行磁构型下,量子点上加微波场可以导致自旋流而 关键词： 微波场 直接隧穿 量子点 泵流     

不同维度模型原子隧穿电离研究

本文数值求解一维和二维模型原子在强激光场作用下含时Schr??dinger方程,研究了在隧穿电离区相同基态能量和相同峰值场强条件下二者的电离速率,发现一维模型计算得到的电离速率比二维的结果大很多.产生该电离速率差别的原因是不同维度下束缚电子所需隧穿的含时势垒的不同.     

双量子阱中光子辅助电子自旋隧穿

采用单电子有效质量近似理论, Floquet理论和传递矩阵方法, 对包含时间周期场的双量子阱中单电子的自旋隧穿特性进行了研究, 对InP/InAs半导体材料进行了数值计算. 重点研究了Rashba型和Dresselhaus型自旋轨道耦合、量子阱结构以及偏压对电子隧穿的影响. 这些结果可以为设计和调控半导体自旋电子器件提供一定的理论依据. 关键词： 光子辅助隧穿 隧穿概率 量子阱     

通过纳米硅中量子点的共振隧穿

用纳米硅(nc-Si∶H)薄膜制成了隧道二极管，并在其I-V曲线上发现了不连续的量子化台阶.二极管的I-V曲线可分成二部分：(1)0—7V，电流随外加电压增大而增大；(2)7—9V，电流随外加电压急剧增大并出现三个量子化台阶.量子化台阶的出现直接与纳米硅中的晶粒有关，根据nc-Si∶H的独特结构，对载流子的传导通道进行了讨论；用通过nc-Si∶H中量子点的共振隧穿对I-V曲线进行了初步解释. 关键词：     

TM光子在受抑全内反射结构中的隧穿时间

用电磁场的能量转移速度定义了TM光子在受抑全内反射结构中的隧穿时间，对所得结果进行了分析和讨论，并把这个结果与TE光子隧穿的时间进行了比较。     

Time Correlation in Tunneling of Photons

I propose to consider photon tunneling as a space-time correlation phenomenon between the emission and absorption of a photon on the two sides of a barrier. Standard technics based on an appropriate counting rate formula may then be applied to derive the tunneling time distribution without any ad hoc definition of this quantity. General formulae are worked out for a potential model using Wigner–Weisskopf method. For a homogeneous square barrier in the limit of zero tunneling probability a vanishing tunneling time is obtained.     

Hawking Tunneling Radiation of a Particle with Electric and Magnetic Charge from Kerr-Newman-Kasuya Black Hole

Extending the Parikh＇s quantum tunneling method of an uncharged particle, we investigate the quantum radiation characteristics of a particle with electric and magnetic charge via tunneling from the event horizon of the Kerr-Newman Kasuya black hole. The derived result supports the Parikh＇s opinion and the correction to the thermal spectrum is of precisely the form that satisfies the underlying unitary quantum theory, and finally provides a might explanation to the black hole information puzzle.     

钻石中硼受主电荷转移引发磷光的直接证据

受主元素硼与不带电荷的替位硼进行电荷重组会导致钻石发出磷光,但Ⅱb型钻石硼含量较高,难以为电荷重组与磷光的相关性提供直接证据。作者针对一粒在常光环境下近无色的钻石,利用DiamondViewTM的深紫外强光源照射样品,使之产生蓝绿色磷光,结合前人研究,推断该类型磷光与含硼元素有关。采集样品红外光谱,在磷光消退前,谱图呈现2 803 cm-1吸收峰,磷光消失后采集的红外谱图不显示2 803 cm-1峰。这一实验中受主硼在紫外光激发下失去电子,成为不带电荷的替位硼原子(B0),B0浓度升高超过红外光谱检测限,红外光谱识别到B0的存在,即引发2 803 cm-1吸收峰。处于激发态的电子返回基态与亚稳态的B0结合过程释放出光子产生磷光。该实验首次直接证实了硼受主与无电荷替位硼之间的电荷重组转移会引发钻石磷光。     

利用扫描隧道显微镜在溶液中直接观测过渡族金属硫属化合物

本文利用自制的溶液扫描隧道显微镜在溶液环境下直接观测到TiSe₂、MoTe₂和TaS₂样品的原子分辨率图像. 通过将单晶样品在溶液中直接解理,可以保护解理过的新鲜样品表面在几个小时内不会被严重污染. 利用自行搭建的溶液扫描隧道显微镜,首先观察到了TiSe₂活泼样品的原子分辨率图像,并观察到了TiSe₂表面所特有的点缺陷和三角形缺陷结构. 此外,还观察到了MoTe₂的原子分辨率超结构和TaS₂表面的电荷密度波结构. 结果表明：在室温、溶液环境下能更高效的研究过渡族金属硫属化合物等活泼样品的表面电子态结构,同样适用于溶液环境下的电催化和电化学研究.     

Transmission and Dwell Time Oscillations Caused by Coexistence of Tunneling and Propagating in a Trapezoidal Barrier

Abstract A refined one of our exactly solvable trapezoidal barrier potential model [Thin Solids Films, 414 （2002） 136）] for metal-insulator-metal tunnel junctions has Seen presented. According to the refined model, the longitudinal kinetic energy （ExL） and the effective mass （m^＊L） of the electron8 in the electrode on the left of the barrier distinguish from that on the right. It is found that as ExL is greater than the shorter side of the resultant trapezoidal barrier potential, there will be a coexistence of the tunneling and propagating in the barrier. The results demonstrate that the damped oscillating electron waves localized in the propagating barrier subregion lead to the oscillation and enhancement in the transmission coefficient DT and dwell time TD. For the barrier height φ1=2.6 eV and φ2 = 1.4 eV, the width d=22 A and ExL = 1.0 eV, DT and TD have a maximum of 0.054 and 0.58x10^-15 s at V = 2.04 V and 2.18 V, respectively. This suggests that a real tunneling may be a hybrid.     

Quantum Tunneling of a Dipolar Bose-Einstein Condensate in Optical Lattice

We study quantum tunneling of a dipolar Bose-Einstein condensate in optical lattice when the spin system initially is prepared in a squeezed coherent state. It is found that there exists quantum tunneling between lattices l and l ＋ 1, l and l - 1, respectively. In particular, when the optical lattice is infinitely long and the spin excitations are in the long-wavelength limit, quantum tunneling disappears between lattices l and l ＋ 1, and that l and l - 1. Correspondingly, the magnetic soliton appears.     

Tunneling through a Metal/Polymer Interface Containing a Thin Oxide Layer: Discussion of the Consequences of Oxide Presence on Charge Injection

The charge injection from oxidized metal electrodes into conjugated polymer thin films is calculated and compared with ideal metal/polymer interfaces. The presence of the oxide layer has a major influence on the magnitude of the tunneling current as well as on its behavior with applied voltage. It was also found that the fitting of the simple Fowler-Nordheim model for triangular barriers to the obtained current-voltage data from the oxidized interfaces leads to incorrect values of the potential barrier height at the metal/polymer interface. Prediction and its consequences on charge injection control in organic devices are discussed.     

Tunneling time and the post-tunneling position of an electron through a potential barrier in an anisotropic semiconductor

Tunneling time and post-tunneling position of an electron incident on a heterostructure grown on anisotropic materials are derived by solving an effective mass equation including off-diagonal effective mass tensor elements. The effects of different effective masses for a heterostructure junction are also included.