| Author: | Wu, Pak Hong Raymond |
| Title: | Critical behavior of the random-bond clock model |
| Degree: | M.Phil. |
| Year: | 2013 |
| Subject: | Mathematical physics. Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Applied Physics |
| Pages: | 91 leaves : ill. ; 30 cm. |
| Language: | English |
| Abstract: | The critical behavior of the clock model in two-dimensional square lattice is studied numerically using Monte Carlo method with Wolff algorithm. The Kosterlitz-Thouless (KT) transition is observed in the six-state clock model, where an intermediate phase exists between the low-temperature ordered phase and the high-temperature disordered phase. The bond randomness is introduced to the system by assuming a Gaussian distribution for the coupling coefficients with the mean μ=1 and different values of variance, from σ²=0.1 to σ²=3.0. An abrupt jump in the helicity modulus at the transition, which is the key characteristic of the KT transition, is verified with a stability argument. The critical temperature Tc for both pure and disordered systems is determined from the critical exponent η(Tc)=1/4. The results showed that a small amount of disorder (small σ) reduces the critical temperature of the system, without altering the nature of transition. However, a larger amount of disorder changes the transition from the KT-type into that of non-KT-type. |
| Rights: | All rights reserved |
| Access: | open access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b26392239.pdf | For All Users | 4.13 MB | Adobe PDF | View/Open |
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