Mottronics and new physical phenomena explored by electrostatic carrier density control.

2014 Fiscal Year Final Research Report

• Project/Area Number: 24244062
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: INOUE Isao 独立行政法人産業技術総合研究所, 電子光技術部門強相関エレクトロニクス研究グループ, 主任研究員 (00356502)
• Research Collaborator: KUMAR Neeraj ; KITO Ai ; EYVAZOV Azar B. ; PANAGOPOULOS Christos ; STOLIAR Pablo ; ROZENBERG Marcelo J. ; JIMÉNEZ David
• Project Period (FY): 2012-05-31 – 2015-03-31
• Keywords: 負の静電容量 / モットFET / サブスレショルド・スイング / 易動度 / 有機無機積層ゲート絶縁膜 / 擬似モット転移 / スピン軌道相互作用 / パーコレーション

Outline of Final Research Achievements

A field effect transistor (FET) with a single-crystalline SrTiO3 (STO) channel of 2-20μm length and with a HfO2/Parylene-C double-layer gate insulator was developed in this research. Both the subthreshold swing (170mV/dec) and the carrier mobility (10cm2/Vs) at room temperature corroborate that the almost defect-free high-quality channel was created on STO. This is because the extremely inert Parylene-C is able to prevent the STO surface from deterioration, even though the thickness of Parylene-C is only 6nm. The sheet carrier density of the channel estimated by Hall effect measurement was 1e14/cm2; ten times as large as the value expected from the measured and invariant capacitance of the gate insulator. This unusual and surprising result can be explained by the appearance of negative capacitance, i.e., the negative compressibility of the quasi 2D metal on the STO surface when a correlation gap is closed at a kind of Mott transition. Unexpectedly, Mott FET was demonstrated on STO.

Free Research Field

物性物理学