ISSP - The institute for Solid State Physics

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Uwatoko Group
Professor
UWATOKO,
Yoshiya

Research Associate
GOUCHI,
Jun

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The high-pressure group has been studying various materials under high-pressure conditions in combination with low temperature and/or strong magnetic field. Nowadays, the techniques combining these multi-extreme conditions have become popular and indispensable for researches in solid state physics. However, the developments of these techniques that can realize in-situ measurements under multiple extreme conditions are often challenging and require sophisticated considerations. This group has devoted numerous efforts in developing such advanced high-pressure techniques and in studying the strongly correlated electronic systems, which is one of the most important themes in modern solid state physics. Considering the fact that many mysterious phenomena in strongly correlated electronic systems result from the electron-phonon and electron-electron interactions, we foresee the discovery of many unknown phenomena under multi-extreme conditions because high pressure offers an effective knob in tuning the inter-atomic distances and the density of electronic state that controls the degree of complex interactions.

CrAs adopts the orthorhombic MnP-type structure with a first-order anti- ferromagnetic transition at TN = 265 K. The first-order TN can be suppressed quickly by the external pressure or substitution by P. And then, the unconventional bulk superconductivity with Tc ≈ 2 K emerges influence of magnetic fluctuation at critical area. (a) : The (0, 0, 2-δ) magnetic Bragg peak for CrAs under different pressures at 4 K. (b) : An updated T-P phase diagram of CrAs showing the complete suppression of Tc around 45 kbar. The coefficient A for CrAs displays an apparent enhancement around Pc ≈ 10 kbar. (DH : double helical order, SC : superconductivity, PM : paramagnetism)

Research Subjects

  1. Search for new physical phenomena under multi extreme conditions
  2. Study of the pressure induced phase transition phenomena as like superconductivity
  3. Development of high pressure apparatus and confirmation of physical property measurement techniques under the multi extreme conditions