题目：Fermi surface reconstruction by charge order in the pseudogap phase of underdoped copperoxides

报告人：Cyril Proust  研究员

                 法国国家强磁场实验室

时间：2015年10月28日上午10:00

地点：国家脉冲强磁场科学中心B206

报告摘要：

Over the last years, quantum oscillation measurements have shown that the Fermi surface of underdoped cuprates suffer a drastic modification compare to the large hole-like cylinder observed in the overdoped side. Many studies such as NMR measurements, x-ray scattering point to a reconstruction of the Fermi surface due to charge density wave (CDW). Fermi-surface reconstruction and charge modulations are two universal signatures of underdoped cuprates, which begs the following questions: what is the impact of charge order on the electronic properties of underdoped cuprates? Is the Fermi surface seen by quantum oscillations compatible with a reconstruction by CDW modulations?

After an introduction starting from the observation of quantum oscillations to the discovery of charge order in cuprates, I will present thermodynamic and transport measurements in underdoped cuprates performed in high magnetic fields demonstrating that a phase transition takes place at low temperature. Compelling evidence that the Fermi surface of YBa2Cu3Oy is reconstructed by the CDW order detected by x-ray diffraction comes from the recent discovery of an additional small hole-like pocket in quantum oscillations measurements. The consistency between our quantum oscillation measurements and models of Fermi-surface reconstruction by the CDW order will be discussed.

报告人简介：

Cyril Proust现任法国国家强磁场实验室研究员。1996年11月-1999年11月于法国图卢兹的凝聚态物理实验室获得固体物理专业博士学位。1999年12月-2001年9月，在加拿大多伦多Taillefer教授团队攻读博士后。2001年10月-2011年9月，在法国图卢兹的国家脉冲强磁场实验室担任初级研究员。2011年10月至今，在法国图卢兹的国家脉冲强磁场实验室担任资深研究员。除此之外，Cyril Proust研究员还在美国国家强磁场实验室，英国卡文迪什实验室，法国格勒诺布尔强磁场实验室，和巴黎高等物理和化学工业学院做过科学研究。

Cyril Proust研究员主要研究强关联体系的电子性质，比如准二维有机（超导）导体、高温超导体和重费米子体系。目前他已被广泛认可为强磁场中测量输运性质，特别是磁电阻中的量子振荡（舒勃尼科夫-德哈斯效应），霍尔效应和热电效应领域的专家。同时他在极低温热导和强磁场中的超声测量方面也具有丰富的经验。

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