Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Seebeck effect studies in the charge density wave state of organic conductor α-(BEDT–TTF) 2 KHg(SCN) 4

Journal Article · · Physica Scripta
; ;
Angular, magnetic field and temperature dependence of the interlayer Seebeck effect of the multiband organic conductor $$\alpha -{(\mathrm{BEDT}-\mathrm{TTF})}_{2}\mathrm{KHg}{(\mathrm{SCN})}_{4}$$ is experimentally studied at temperatures down to 0.55 K and fields up to 31 T in a wide range of angles. The background magnetic field and angular component of the Seebeck effect as well as the magnetic quantum oscillations that originate from the closed Fermi surface orbits are analyzed. The background interlayer Seebeck effect components show that above certain tilt angle of the magnetic field and above the kink field there is another CDW state in $$\alpha -{(\mathrm{BEDT}-\mathrm{TTF})}_{2}\mathrm{KHg}{(\mathrm{SCN})}_{4}$$, between previously known CDW0 and CDWx states, in agreement with magnetoresistance and magnetization studies in this material. Our observations show that this state possesses some of the properties of the CDW0 state. The Fermi surface in the third CDW state is still reconstructed but less imperfectly nested as expected as this state develops above the kink field. The temperature dependence of the interlayer Seebeck effect reveals that this state is developed at temperatures below 3 K and at field orientations around the second AMRO maximum. In addition, for the first time, a detailed T - θ phase diagram of $$\alpha -{(\mathrm{BEDT}-\mathrm{TTF})}_{2}\mathrm{KHg}{(\mathrm{SCN})}_{4}$$ based purely on Seebeck effect measurements is presented. We find that other states and transitions, beside the CDW states, also exist in a given temperature and angular range that have not been previously reported. These observations change the whole picture about the transport processes in the organic conductor $$\alpha -{(\mathrm{BEDT}-\mathrm{TTF})}_{2}\mathrm{KHg}{(\mathrm{SCN})}_{4}$$ and allow to better understand the complex nature of the CDW order in this and similar compounds.
Research Organization:
Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab)
Sponsoring Organization:
USDOE
OSTI ID:
1982453
Journal Information:
Physica Scripta, Journal Name: Physica Scripta Journal Issue: 12 Vol. 96; ISSN 0031-8949
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English

References (20)

Phase boundary in the dimensionality of angle-dependent magnetoresistance oscillations in the charge-transfer salt journal November 1996
Competition between Pauli and orbital effects in a charge-density-wave system journal October 2000
High Magnetic Fields:  A Tool for Studying Electronic Properties of Layered Organic Metals journal November 2004
Critical state in a low-dimensional metal induced by strong magnetic fields journal December 2000
Organic Conductors and Superconductors: New Directions in the Solid State journal August 1993
Angle dependent magnetothermopower of α-(ET)2KHg(SCN)4 journal October 2011
Crystal and Electronic Structures of (BEDT–TTF)2[MHg(SCN)4](M=K and NH4) journal August 1990
Orbital quantization in the high-magnetic-field state of a charge-density-wave system journal November 2003
Magnetic quantum oscillations in the charge-density-wave state of the organic metals α-(BEDT-TTF)2MHg(SCN)4with M = K and Tl journal April 2014
High-field magnetotransport and Fermi-surface topology in the novel quasi-two-dimensional organic conductor bis(ethylenedithiolo)tetrathiafulvalenium mercuric postassium thiocyanate, (BEDT-TTF)2KHg(SCN)4 journal March 1990
Mysterious ground states in the organic conductor α-(BEDT-TTF)2KHg(SCN)4 : Mixed SDW and CDW? journal March 1995
The angular magnetothermoelectric power of a charge density wave system journal June 2012
High-field studies of the H-T phase diagram of α-(BEDT-TTF)2KHg(SCN)4 journal February 1997
Anisotropy of the Seebeck Coefficient in the Cuprate Superconductor YBa 2 Cu 3 O y : Fermi-Surface Reconstruction by Bidirectional Charge Order journal September 2017
Thermopower Quantum Oscillations in the Charge Density Wave State of the Organic Conductor $$\upalpha $$ α -(BEDT-TTF) $$_{2}\text {KHg}(\text {SCN})_{4}$$ 2 KHg ( SCN ) 4 journal February 2019
Density-wave instability inα−(BEDT-TTF)2KHg(SCN)4studied by x-ray diffuse scattering and by first-principles calculations journal October 2010
Magnetothermopower study of the quasi-two-dimensional organic conductorα−(BEDT−TTF)2KHg(SCN)4 journal May 2002
Low-frequency method for magnetothermopower and Nernst effect measurements on single crystal samples at low temperatures and high magnetic fields journal May 2001
Electronic Structure of the $\mathsf{\alpha}$-(BEDT-TTF)$\mathsf{_2}$MHg(XCN)$\mathsf{_4}$ (M = Tl, K, NH$\mathsf{_4}$; X = S, Se) and Related Phases. Synthesis and Crystal Structure of the New Stable Organic Metal $\alpha$-(BEDT-TTF)$\mathsf{_2}$TlHg(Se$\mathsf{_{\rm 1-x}}$S$\mathsf{_{\rm x}}$CN)$\mathsf{_4}$ (x = 0.125) journal December 1996
Argument for charge density wave sub-phases in the ground state of α-(BEDT-TTF)2KHg(SCN)4 journal July 1998

Similar Records

Magnetic breakdown in the organic conductor {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} in magnetic fields of up to 60 T
Journal Article · Tue Sep 01 00:00:00 EDT 1998 · Physical Review, B: Condensed Matter · OSTI ID:658494
Microscopic evidence for a partially gapped density wave state in {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} in high magnetic fields.
Journal Article · Sun Jan 31 23:00:00 EST 1999 · Solid State Commun. · OSTI ID:942457
Giant Angular Nernst Effect in the Organic Metal α-(BEDT-TTF)2KHg(SCN)4
Journal Article · Mon Jan 09 19:00:00 EST 2023 · Magnetochemistry · OSTI ID:2425015

Related Subjects

Physics