title: Unusual Mott transition in multiferroic PbCrO3.
abstract: The Mott insulator in correlated electron systems arises from classical Coulomb repulsion between carriers to provide a powerful force for electron localization. Turning such an insulator into a metal, the so-called Mott transition, is commonly achieved by "bandwidth" control or "band filling." However, both mechanisms deviate from the original concept of Mott, which attributes such a transition to the screening of Coulomb potential and associated lattice contraction. Here, we report a pressure-induced isostructural Mott transition in cubic perovskite PbCrO3. At the transition pressure of ∼3 GPa, PbCrO3 exhibits significant collapse in both lattice volume and Coulomb potential. Concurrent with the collapse, it transforms from a hybrid multiferroic insulator to a metal. For the first time to our knowledge, these findings validate the scenario conceived by Mott. Close to the Mott criticality at ∼300 K, fluctuations of the lattice and charge give rise to elastic anomalies and Laudau critical behaviors resembling the classic liquid-gas transition. The anomalously large lattice volume and Coulomb potential in the low-pressure insulating phase are largely associated with the ferroelectric distortion, which is substantially suppressed at high pressures, leading to the first-order phase transition without symmetry breaking.
authors.affiliation: Institute of Atomic & Molecular Physics, Sichuan University, Chengdu 610065, China; High Pressure Science & Engineering Center and Physics Department, University of Nevada, Las Vegas, NV 89154; Los Alamos Neutron Science Center and Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545; shanminwang@gmail.com duanweihe@scu.edu.cn Yusheng.Zhao@unlv.edu.
authors.forename: Shanmin
authors.initials: S
authors.lastname: Wang
authors.affiliation: High Pressure Science & Engineering Center and Physics Department, University of Nevada, Las Vegas, NV 89154; Los Alamos Neutron Science Center and Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545; National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
authors.forename: Jinlong
authors.initials: J
authors.lastname: Zhu
authors.affiliation: High Pressure Science & Engineering Center and Physics Department, University of Nevada, Las Vegas, NV 89154;
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Los Alamos Neutron Science Center and Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545; National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Yu
authors.affiliation: Los Alamos Neutron Science Center and Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545;
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Institute of Atomic & Molecular Physics, Sichuan University, Chengdu 610065, China;
authors.forename: Wendan
authors.initials: W
authors.lastname: Wang
authors.affiliation: High Pressure Science & Engineering Center and Physics Department, University of Nevada, Las Vegas, NV 89154; High Pressure Collaborative Access Team, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL 60439;
authors.forename: Ligang
authors.initials: L
authors.lastname: Bai
authors.affiliation: US Synthetic Corporation, Orem, UT 84058;
authors.forename: Jiang
authors.initials: J
authors.lastname: Qian
authors.affiliation: Department of Physics, University of Florida, Gainesville, FL 32611;
authors.forename: Liang
authors.initials: L
authors.lastname: Yin
authors.affiliation: Department of Physics, University of Florida, Gainesville, FL 32611;
authors.forename: Neil S
authors.initials: NS
authors.lastname: Sullivan
authors.affiliation: National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors.forename: Changqing
authors.initials: C
authors.lastname: Jin
authors.affiliation: Institute of Atomic & Molecular Physics, Sichuan University, Chengdu 610065, China; shanminwang@gmail.com duanweihe@scu.edu.cn Yusheng.Zhao@unlv.edu.
authors.forename: Duanwei
authors.initials: D
authors.lastname: He
authors.affiliation: Institute of Atomic & Molecular Physics, Sichuan University, Chengdu 610065, China;
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.affiliation: High Pressure Science & Engineering Center and Physics Department, University of Nevada, Las Vegas, NV 89154; Los Alamos Neutron Science Center and Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545; shanminwang@gmail.com duanweihe@scu.edu.cn Yusheng.Zhao@unlv.edu.
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Zhao
keywords: Mott criticality; Mott transition; PbCrO3; isostructural transition; multiferroics