Recent content by Pedro Roman

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    Heat engine that uses a rubber band (Thermodynamics)

    Let just say that we have a cycle as the one showed in the figure, which follows the following equation of state, J=aLT, and for that let us calculate the total work and the heat absorbed, in that sense one is able to compute the 'efficiency' of the 'heat engine'. This is just a textbook...
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    Heat engine that uses a rubber band (Thermodynamics)

    Nota that the path a to b is isothermal since J is proportional to L, then we can find the value of T_a and T_b using the equation of state and the figure. We have, \begin{equation} J_0=\alpha L_0T_b \end{equation} or \begin{equation} T_b=T_a=\frac{J_0}{\alpha L_0}=T_0 \end{equation} Also, by...
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    A Localized states and density of states

    Thanks for your very detailed answer DrDu, I am looking for surface states and a way of knowing where they are located. I ended up using the wave functions of the system (see my last comment to your answers). You're right, what I meant is that I have a two dimensional nanoribbon (a graphene...
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    A Localized states and density of states

    Thanks for your answer DrDu. Since the system is finite, as you said, any discrete eigenvalue must correspond to a localized state. But I consider that a localized state near the center of the sample is a bulk state. Whereas localized states near the edges are edge states. I hope this make...
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    A Localized states and density of states

    Thanks for your answer DethbyGreen. You're right, along the y-direction the system is not periodic, hence I have to calculate the DOS numerically, what I already did. On the other hand, I am not looking for zero edge modes, instead I am looking for edge states, which are not necessarily zero...
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    A Localized states and density of states

    Hello, Let's suppose we have a two dimensional lattice which is periodic along certain direction, say x-direction, allowing us to define a quasi momentum k_x. The lattice is not periodic along the y-direction (perpendicular to x-direction). Therefore, we are able to obtain the band structure...
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    Density of States of a metal at Fermi level

    I want to know because when you consider a model system of interacting electron gas in the so-called jellium model, the thermodynamic potential to first order of interaction, it turns out, that stopping at first order leads to the density of states at Fermi level vanishes. So, it argues that no...
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    Density of States of a metal at Fermi level

    I have no reason, but what does it happen when the gradient of the energy diverges logarithmically at Fermi level, which implies that the density of states at Fermi level will be zero? Thanks a lot for answering nasu!
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    Density of States of a metal at Fermi level

    Why can not the density of states of a metal at Fermi level be zero? Thanks!
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    Dissociation Energy (Modern physics)

    Homework Statement Hello, the question is, does the binding energy of a molecule is greater than or equal to the dissociation energy? Homework Equations A molecule exists because its energy is less than that of the system of separate noninteracting atoms: Mc²∠Ʃ mi c² Here M is...
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