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4시 20분부터 제1과학관 31214 e+강의실에서 간단한 다과를 제공합니다.

아 래

Title: Hidden-in-bulk Phase Transitions in Artificial Quantum Materials

Speaker: 이  대  수 교수님 (Department of Physics, POSTECH)

Date & Time: Nov. 7. (Wed.) 2018 4:30 PM

Place: Natural Science 1,  Room No. 31214

Abstract: A major challenge in condensed matter physics is predictive control of physical properties and functions in complex materials. In this talk, I will demonstrate a heterostructuring approach to engineer free-energy landscape and stabilize a new state, otherwise away from equilibrium, in a controlled way. First, as a model material, I choose an archetypal correlated material VO2, which has the insulating ground state of the monoclinic phase. A designed heterostructure suppresses the electronic correlation without changing the crystal structure in this otherwise correlated insulator. It stabilizes a nonequilibrium metallic state, leading to an isostructural metal-insulator transition. In addition, I will show emergence of an ordered ferroelectric state in ultrathin films of an otherwise non-ferroelectric SrTiO3. This challenges the long-standing notion that a collective order (e.g., ferroelectricity) is inevitably suppressed at the scale of a few nanometers. Last, I will shortly discuss on how the atomic-layer-controlled heterostructuring can manipulate complex phase transitions in a predictive manner. These discoveries highlight the ability to control the hidden-in-bulk phase transitions in heterostructures, as well as provide new insights for exploring complex materials.