101,719 research outputs found
The structural, mechanical, electronic, optical and thermodynamic properties of t-XAs (X Si, Ge and Sn) by first-principles calculations
The structural, mechanical, electronic, optical and thermodynamic properties
of the t-XAs (X Si, Ge and Sn) with
tetragonal structure have been investigated by first principles calculations.
Our calculated results show that these compounds are mechanically and
dynamically stable. By the study of elastic anisotropy, it is found that the
anisotropic of the t-SnAs is stronger than that
of t-SiAs and
t-GeAs. The band structures and density of states
show that the t-XAs (Si, Ge and Sn) are
semiconductors with narrow band gaps. Based on the analyses of electron density
difference, in t-XAs As atoms get electrons, X
atoms lose electrons. The calculated static dielectric constants,
, are 15.5, 20.0 and 15.1 eV for
t-XAs (X Si, Ge and Sn), respectively. The
Dulong-Petit limit of t-XAs is about 10 J
molK. The thermodynamic stability successively
decreases from t-SiAs to
t-GeAs to t-SnAs.Comment: 14 pages, 10 figures, 6 table
Fast entanglement of two charge-phase qubits through nonadiabatic coupling to a large junction
We propose a theoretical protocol for quantum logic gates between two
Josephson junction charge-phase qubits through the control of their coupling to
a large junction. In the low excitation limit of the large junction when
, it behaves effectively as a quantum data-bus mode of a
harmonic oscillator. Our protocol is efficient and fast. In addition, it does
not require the data-bus to stay adiabatically in its ground state, as such it
can be implemented over a wide parameter regime independent of the data-bus
quantum state.Comment: 5 pages, 1 figur
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