Scholarlink

<p>NbSe<sub>2</sub> is a transition metal dichalcogenide with a two-dimensional nature, showing superconducting (SC) and charge density properties. Moreover, a 1T phase can be made in the film, which has a different property from the bulk dominant 2&#xa0;H phase, in which Mott insulator behavior is actively discussed. We observed the surface with STM at 400 mK and injected RF signal (1&#xa0;GHz and 15&#xa0;Hz) at the tunneling junction. We detected two quasi-particle (QP) states at the end of the SC gap, which split with the increase of the RF power specified by the electric field at the tunneling junction, V<sub>AC</sub>. A previous STM experiment with 65&#xa0;GHz RF on a vanadium surface observed multiple replicas of the QP peak. However, our experimental result using 1&#xa0;GHz RF shows a widening of QP features with two enhanced peaks shifted by ~ ± eV<sub>AC</sub> from the original QP positions. The behavior was well reproduced by a simulation using a well-known Tien-Gordon model, whose results indicate that the disappearance of multiple peaks is due to the low frequency of the RF signal. In addition, two enhanced peaks at ~ ± eV<sub>AC</sub> are deduced from the Bessel function behavior. The energy shift from the original peak linearly changes with eV<sub>AC</sub>. We apply this technique to examine the property change at the domain boundary of the 2&#xa0;H and 1T phase of the NbSe<sub>2</sub> surface. We found the superconducting gap decreases when we move the tip from the 2&#xa0;H domain into the 1T domain. Moreover, the injection of RF splits a QP peak into two enhanced peaks, whose energy separation is linear with the electric field at the RF generator for both phases. However, the linear energy separation with V<sub>AC</sub> shows different coefficients between the 2&#xa0;H and 1T phases. We conclude that the different coefficient is due to the change of actual V<sub>Ac</sub> on the two domains originating from a different dielectric constant and shielding efficiency for the electric field of RF.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

RF injection scanning tunneling spectroscopy of a superconducting NbSe2 surface

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年7月1日

查看全文
  • Md. Arafat Ali,
  • Zhipeng Wang,
  • Mohammad Ikram Hossain,
  • Ferdous Ara,
  • Syed Mohammad Fakruddin Shahed,
  • Tadahiro Komeda

摘要

NbSe2 is a transition metal dichalcogenide with a two-dimensional nature, showing superconducting (SC) and charge density properties. Moreover, a 1T phase can be made in the film, which has a different property from the bulk dominant 2 H phase, in which Mott insulator behavior is actively discussed. We observed the surface with STM at 400 mK and injected RF signal (1 GHz and 15 Hz) at the tunneling junction. We detected two quasi-particle (QP) states at the end of the SC gap, which split with the increase of the RF power specified by the electric field at the tunneling junction, VAC. A previous STM experiment with 65 GHz RF on a vanadium surface observed multiple replicas of the QP peak. However, our experimental result using 1 GHz RF shows a widening of QP features with two enhanced peaks shifted by ~ ± eVAC from the original QP positions. The behavior was well reproduced by a simulation using a well-known Tien-Gordon model, whose results indicate that the disappearance of multiple peaks is due to the low frequency of the RF signal. In addition, two enhanced peaks at ~ ± eVAC are deduced from the Bessel function behavior. The energy shift from the original peak linearly changes with eVAC. We apply this technique to examine the property change at the domain boundary of the 2 H and 1T phase of the NbSe2 surface. We found the superconducting gap decreases when we move the tip from the 2 H domain into the 1T domain. Moreover, the injection of RF splits a QP peak into two enhanced peaks, whose energy separation is linear with the electric field at the RF generator for both phases. However, the linear energy separation with VAC shows different coefficients between the 2 H and 1T phases. We conclude that the different coefficient is due to the change of actual VAc on the two domains originating from a different dielectric constant and shielding efficiency for the electric field of RF.