Effect of vacancy defects on the Josephson current in zigzag graphene narrow strips

Document Type : Original Article

Authors

1 Department of Physics, Alzahra University, Tehran, Iran

2 Department of Physics, Alzahra University​, Tehran, Iran

3 Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran

Abstract

We investigate the Josephson current in a superconductor/zigzag graphene narrow strip/superconductor (Sc-ZGNS-Sc) junction, with vacancy defects. For this purpose, we extend a recursive Green’s function based numerical method to ZGNSs and take into account the effect of vacancies including random single vacancy distributions and also chain-like linear defects. We investigate how the Josephson current is affected by the length and the width of the strip and the concentration of the vacancies. We find that the Josephson current exhibits an exponentially dependence on the vacancy concentration. The exponent coefficient is a nonlinear function of the length of the lattice and the vacancy concentration. For the width dependence we find a linear relation between the Josephson current and the width of the ZGNS which propose a semi classical treatment of the electron transport in this system. Finally, we study the effect of chain-like linear defects and compare them with randomly distributed single vacancies.

Keywords

Article Title [Persian]

اثر عیوب تهی جائی بر جریان جوزفسونی در نانوریبون زیگزاگی

Authors [Persian]

  • سمیه زارعی 1
  • وحید دادمهر 2
  • حسین حکیمی پژوه 1
  • زهرا فرائی 3

1 گروه فیزیک، دانشگاه الزهرا، تهران، ایران

2 گروه فیزیک، دانشگاه الزهرا، تهران، ایران

3 گروه فیزیک، دانشگاه تحصیلات تکمیلی علوم پایه گاوازنگ، زنجان، ایران

Abstract [Persian]

ما جریان جوزفسون را در یک اتصال ابررسانا/نوار باریک زیگزاگ گرافن/ابررسانا (Sc-ZGNS-Sc) با نقص های تهی جائی بررسی می کنیم. برای این منظور ، ما روش عددی مبتنی بر تابع بازگشتی را به ZGNS ها بسط داده و تأثیر تهی جاها شامل توزیع های تک تهی جای تصادفی و نقص های خطی زنجیره ای از تهی جاها را در نظر می گیریم. ما چگونگی تغییر جریان جوزفسون تحت تأثیر طول و عرض نوار و غلظت تحت موقعیت های تهی جاها بررسی می کنیم. دریافتیم که جریان جوزفسون وابستگی نمایی به غلظت تهی جائی دارد. ضریب توان یک تابع غیر خطی از طول شبکه و غلظت تهی جاها است. برای وابستگی جریان جوزفسون به عرض ZGNR ما یک رابطه خطی بین جریان جوزفسون پیدا کردیم که یک سازوکار نیمه کلاسیک از انتقال الکترون در این سیستم پیشنهاد می کند. در نهایت، ما اثر عیوب خطی زنجیره ای را مطالعه می کنیم و آنها را با موقعیت های تهی جائی منفرد به طور تصادفی مقایسه می کنیم.

Keywords [Persian]

  • نوار باریک گرافن
  • جریان جوزفسون
  • عیب تهی جا
  • الگوی شبکه
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